[Q]: How does the sentence end?

While the zen master practiced meditation he replaced the candle with the incense because the 

[A]: incense was fresh.


[Q]: How does the sentence end?

Eric wanted to ascend to political power and Jason did not because 

[A]: Eric was very ambitious.


[Q]: How does the sentence end?

Since Natalie washed the tub while Betty lazily sat on the couch, 

[A]:
Betty was pleased to do none of the work.