Which of the answers seems most natural – although being or despite being?
4. Chen Wei Lin, or “tom60229,” was one of the participants in the 2017 Hearthstone World Championship. He wasn't as popular as the other participants. ________ being an unknown underdog, he won the championship.
a) Instead of
d) Because of
This seems like a problem of TEPS, a TOEFL-like test of South Korea. This test says that "Choose the best answer for the blank", so there can be two grammatically correct answers for one problem although there is only one answer considered right.
In this case (Problem 4), both (b) and (c) seem OK to me. They have a similar meaning, (c) looks grammatically OK and appears to be good if we consider it a perfect participle.
Is this problem asking which is more 'natural'? If so, which of them is most natural? If not, what am I missing here?
I googled 'although being' and 'despite being', and I found both of them, so googling didn't help me.