A reliable source would not be C a biased source because it would be unfair and opinionated. D wouldn't be correct since a personal website seems like it would be very opinionated and not very factual. I was between A and B, but it wouldn't be B a source that does not include the author's credentials since you don't know who the author is or her/his history or education. For all you know, he/she might be a person making stuff up or guessing. This leads me to believe the answer is A.
A well respected, reliable magazine is a very credible source.
I hope this helps:)