Problem 21. (1 paint) Let P(x) be the statement " x understands this problem". Assume the domain of discourse consists of all students. Express the proposition xP(x) as an English sentence. - A. Every student understands this problem. - B. No student understands this problem. - C. There is a student who does not understand this problem. - D. There is a student who understands this problem. - E. There is a single student who understands this problem. - F. There is a single student who does not understand this problem. Now let Q(x) be the statement " x wakes up before 6am".. Express the following sentence in terms of Q(x) and quantifiers (with domain consisting of all students). "There is a student who does not wake up before 6 am." - A. xQ(x) - B. xQ(x) - C. xQ(x)