Let's look at all the answers:
A. Looking away while they're speaking
- this will not help you understand what they're saying and will also likely distract them and make them angry!
B. Thinking about what they're saying
-yes, this is the correct answer! This will also allow you to see if you understood what they said and allow you to ask proper questions afterwards!
C Interrupting them
-no, this will only be a distraction to both of you
D. Thinking about a test in human relations -again not: this will only be a distraction!