Which of the Following Sentences Is Not an Effective Thesis

Multiple Choice

Which of the following sentences is not an effective thesis because it contains more than one idea?

A) People who live in small towns escape many of the hazards of the city.
B) Living in a small town can be boring, but it can provide business opportunities.
C) Moving to a small town required some major adjustments in my life.
D) My roommate's small-town background did not prepare her for life at a large university.