The best way to let someone know that you understand and care about what they are saying is to A. be polite and wait for them to finish talking, then judge them on what they said.
B. give the speaker instances of when a similar thing happened to you to distract them from their problem
C. nod your head, look them in the eye, and show concern for what they are saying
D. stop the speaker from continuing if there is something you need them to repeat or explain.