My best guess is B. The others look questionable
The word, behind, tells you where or something is in relation to something else. It also has a symbol hat is ;-)
the answer is
Ambifuos reference.
It is not clear that the <em><u>it </u></em>as a pronoun reference refers to the fact of singing higher or being different from others.
Because she promised them to Maggie when she marries John Thomas
"I promised to give them quilts to Maggie, for when she marries John Thomas"
The bold is from the story