Peers has two meanings:
1) verb: to look or gaze. For example: He peers at the puppy through the window. (that is, he looks at the puppy through the window)
2) noun: Individuals who are comparable on some given metric. For example: My peers and I met to discuss issues which impacted our lives.
Peer's refers to something belonging to a single peer (definition two above).
For example: I thought that my peer's sweater looked very nice on him.
Peers' refers to something belonging to a group of peers (definition two above). For example: As a group, my peers' achievements are very impressive!
So for your sentence on taking advice, I would assume that you would want
to use "peer's", because it refers to the advice which comes from a single peer.
Answer:
the first one because it uses a quote from the text correctly and reading that answer gave me more information than the rest.
My best guess would be A.
This is true, as sales people will often have biased opinions on some topics.