In Which of the Following Explanations Is the Hypothesis Underlined

In which of the following explanations is the hypothesis underlined?

A) Pearl Jam stopped for supper in our town because it was on their tour route.
B) Because my sister-in-law was born in Lithuania, we decided to visit there for a week.
C) The rubberized case is the best one, since it protects the phone if it is dropped.
D) The fourth movie in the series wasn't as good, because the writers scripted it more quickly.
E) We stopped putting seed in our birdfeeder because squirrels were stealing it all.