[Q]: How does the sentence end?

The phone of Donald is a lot better than Adam's because 

[A]: Donald paid extra for his phone.


[Q]: How does the sentence end?

Most people write on desks and not on the carpet because the surface of the 

[A]: desk is flat.


[Q]: How does the sentence end?

After a long discussion, Rebecca wanted fewer pets than Megan for 

[A]:
Rebecca was allergic to the hair.