Which statement best describes an organism that obtains its energy in the absence of free oxygen A?

You can usually pass a multiple guess test even if you know nothing about the subject, just by thinking about what's what. Hemoglobin is in your blood and it transports oxygen, so that's not the answer. Mitochondria have nothing to do with oxygen, so that's not the answer. B and C can not both be true, so one of those is the answer. You have already improved your chances from 25% to 50%. "Fermate" is a musical term (more often spelled 'fermata'), so that's not the answer. B is the answer even if you don't know why.