The Queen's Dagger - 'A' or 'B'? ? ? ? ? ?

The question is between you two,
'A' and 'B'.
If this were a math test,
I would have the answer in a second.
If this were a science test,
I would have the answer in a second.

But there is not a second,
and this is the test of life.

The Queen's Dagger

http://www.poemhunter.com/poem/a-or-b-2/