What is the intense psychological response that often accompanies losing a loved one to death?

Karen cries while saying to her boyfriend, "John, I don't feel as though you love me." John gives Karen a big hug saying, "That's not true, dear, I love you very much." If John's hug is a reinforcer, Karen is _______ likely to cry the next time she feels insecure about her relationship. More specifically, this is an example of ________ reinforcement of Karen's crying behavior.

Fill in the blank(s) with the appropriate word(s).

_______ involves giving positive regard and acceptance at all times and in all situations

a. Conditional positive regard b. Positive reinforcement c. Operant conditioning d. Unconditional positive regard