[Q]: How does the sentence end?

Elena didn't want to invite Betty to the party, because

[A]: Betty was a snobby guest.

[Q]: How does the sentence end?

The regulators decided to help the environment by putting taxes on the train but not the plane because the

[A]: train was inefficient.

[Q]: How does the sentence end?

Jeffrey was angry with Nick because

[A]:
Jeffrey lent him a school book that he destroyed.