When making informed decisions about health products or procedures, it's important to consider
a.
risks, costs, and caution
b.
credibility, risks, and costs
c.
risks, credibility, and friends' referrals
d.
none of the above

The question is asking us: "When making informed decisions about health products or procedures, it's important to consider... We definitely have to consider the risks, if the risks are too high, we might want to decide against a procedure. Another thing we might want to consider is the cost: can we afford the procedure? We should also think: is the source credible? Is the doctor experienced, for example? So the best answer is:

B.credibility, risks, and costs