Which of the following is an indication that an incumbent member of the U.S. House of Representatives has a safe seat?

A -- Campaigning for out-of-state candidates a week before the election.

B -- Taping commercials for a Senate candidate in the opposition party.

C -- Winning the endorsement of the largest union in your district when you're a conservative Republican.

D -- Having an opponent whose national congressional campaign committee reneges on a promise to target funds for him.

E -- Not bothering to raise or spend a penny until the last five weeks of the campaign.

F -- Ridiculing your opponent's candidacy as "demeaning to Congress and an insult to the people who think they can't find someone better qualified."

If you've answered all of the above, you have correctly indentified the situation in six of Maryland's eight congressional districts, where incumbents either have only token opposition or are campaigning as if they had no opposition at all. While colleagues Michael Barnes and Robert Bauman wage expensive and hard-fought battles for reelection, these congressmen have spent the last few months in relatively leisurely fashion for an election year.

Rep. Barbara A. Mikulski left her Third Congressional District in Baltimore last week to lend her support to the "old girl network." She made speeches in New York for Democratic Senate candidate Elizabeth Holtzman and House nominee Mary Anne Krupsak, former lieutenant governor of New York, and in Western Massachusetts for Congressional hopeful Helen (Poppy) Doyle.

Mikulski's challenger is Russell T. Schaffer, 31, who has spent $3,500 from his own pocket because he "thought it was un-American" that Mikulski was unopposed for a second-term two years ago.

Rep. Parren J. Mitchell, a Democrat, has flaunted tradition by making radio commercials for Republican Sen. Charles McC. Mathias. Mitchell also has found time to travel around the country in behalf of the National Task Force on Black Voter Registration.

His opponent, Victor Clark, 35, is a lawyer and assistant manager of a cemetery who has less than $1,00 available to try to unseat the former chairman of the Congressional Black Caucus.

Rep. Marjorie S. Holt, in her quest for a fifth term, has the endorsement of the International Brotherhood of Electrical Workers at the 19,000-employe Westinghouse defense plant near BWI Airport, thanks largely to her hawkish votes on the House Armed Services Committee, which holds the key to continued defense contracts.

Her Democratic opponent, James J. Riley, is a history teacher who won the Democratic nomination in a field of six. Riley and Holt have made a number of joint appearances in the sprawling Fourth District, but Riley has failed to win either money or widespread support, despite the 3-to-1 registration edge enjoyed by Democrats.

Two members of the Maryland delegation had been expected to face serious challenges this year but now are favored.

Rep. Beverly Byron's opponent, State Del. Raymond Beck, the minority leader of the Maryland House of Delegates, has been unable to attract significant support and suffered a major setback when the Republican Congressional Campaign Committee took Byron's Sixth Congressional District off the list of races targeted for financial help.

Rep. Clarence D. Long, the dean of the Maryland congressional delegation, faces, from Republican Helen Delich Bentley, the most serious challenge in his nine-term career. Nonetheless, the official report Long filed with the Federal Election Commission showed that as of Sept. 30, he had no income or expenses in connection with the contest for his Second District seat.

Rep. Glayds Noon Spellman, a three-term Democrat from Prince George's County, meanwhile, has acted as if her opponent's lack of experience is a personal insult. The opponent, Kevin Igoe, a former U.S. budget specialist, is making his first try for elective office. a

In Virginia, only two of the 10 congressional districts offer toss-up races, and both of those are encores. Rep. Joseph L. Fisher (D-10) is facing Republican Frank Wolf for a second consecutive time, and Rep. Hebert E. Harris II (D-8) is being challenged by Stanford E. Parris, the Republican from whom he won the seat in 1974.