Answer: C) The sun is setting later nowadays.
Step-by-step explanation: A progressive verb is a conjugation of a verb that is used to show an action that is in progress (it can be in the past, the present or the future). The structure of a progressive form is: the verb "to be" (conjugated in present, past of future, according to the case) + the present participle of the verb (-ing form). In the given sentence the one that contains a progressive verb is option C, with the verb "is setting".