Which of the Following Sentences Contains an ASSERTED Proposition in a Noun

Multiple Choice

Which of the following sentences contains an ASSERTED proposition in a noun clause?

A) I'm not sure that I deserve to be happy.
B) Many cereal brands are trying to downplay the sugar content of their products.
C) Each teen should consider whether he or she is mature enough to drive a car.
D) Whoever stole the diamond ought to be in jail.
E) I believe that there is good in everyone.