I would say A, binocular vision. ((Not sure though.))
Step-by-step explanation:
Process of elimination. Opposable thumbs could help, but not as much as being able to spot your prey from far away. And what does singular births and just being a mammal help with being a predator? The answer that makes most sense is A. Hope this helps.
A yard is equivalent to 3 feet. If a singular doormat is 2 feet long then two doormats placed in a line would be 4 feet long. 4 > 3 meaning they would be longer than a yard.