The phrase magic bullets in paragraph 4 is closest in meaning to

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Apologies are powerful. They resolve conflicts without violence and restore equilibrium to personal relationships. They can be a sign of strength: proof that the apologizer has the self-confidence to admit a mistake.
Apologies, like so many other communication strategies, begin at home. In the American context, there is ample evidence that women are more inclined to offer an expression of contrition than men.
One woman, for example, told me that her husband's resistance to apologizing makes their disputes go on and on. Once, after he forgot to give her a particularly important telephone message, she couldn't get over her anger, not because he had forgotten (she realized anyone can make a mistake) but because he didn't apologize. "Had I done something like that," she said, "I would have fallen all over myself saying how sorry I was... I felt as though he didn't care." When I asked her husband for his side of the story, he said apologizing would not have repaired the damage. "So what good does it do?" he wondered.
The good it does is to cement the relationship. By saying he was sorry - and saying it as if he meant it - he would have conveyed that he felt bad about letting her down. Showing that you empathize provides the element of contrition, remorse, or repentance that is central to apologies - as does the promise to make amends and not repeat the offense. In the absence of these, why should the wife trust her husband not to do it again?
Apologies can be equally powerful in day-to-day situations at work. One company manager told me that they were magic bullets. When he admitted to subordinates that he had made a mistake and then expressed remorse, they not only forgave him but became even more loyal. Conversely, when I asked people what most frustrated them in their work lives, co-workers refusing to admit fault was a frequent answer.
(Adapted from Contrite Makes Right in Civilization Magazine by Deborah Tannen)