The correct choice is option A.
Answrs: Part a) "Facts from a documentary.." This is talking about the benefits of artificial organs instead of donated ones.
Part b) "There are several ..." Because it is a sentence that is likely to precede facts. The others are opinions about how something 'SHOULD' be, and aren't presenting facts or claiming something.The first one 3ven says "I think..." which is clearly an opinion.
Yes it is a metaphor because he does not literally have a key to her heart. It is just figurative speaking.
