[Q]: How does the sentence end?

I tried to fit the paper under the door, but it wouldn't go because the 
OPTIONS:
- paper was too thick.
- door was too thick.

[A]: paper was too thick.


[Q]: How does the sentence end?

The actor tried to use the book to develop a new personality but the 
OPTIONS:
- personality was too complicated.
- book was too complicated.

[A]: book was too complicated.


[Q]: How does the sentence end?

Robert trusted Leslie to broker his money online because, between the two of them, 
OPTIONS:
- Robert was the amateur investor.
- Leslie was the amateur investor.

[A]:
Robert was the amateur investor.