What are defensive behaviors or defense mechanisms and why do we use them?

Defense mechanisms, or behaviors, are behaviors people use to separate themselves from unpleasant events, actions, or thoughts. These strategies may help people put distance between themselves and unwanted feelings, such as guilt or shame. Denial is one of the more common defense mechanisms. It happens when you refuse to accept reality or facts. Projection is another defensive mechanism, you may have some thoughts or feelings  about another person and they  may make you uncomfortable. If you project those feelings, you’re misattributing them to the other person.

the correct answer is d

again, you should probably take him to the vet. goodluck