Determine if the sequence is monotonic and if it is bounded. 20gn an n! , n21 Select the correct answer below and, if necessary, fill in the answer box(es) to complete your choice. O A. {an} is monotonic because the sequence is nonincreasing. The sequence has a least upper bound when n = but is unbounded because it has no lower bound. (Simplify your answer.) O B. {an} is not monotonic. The sequence is bounded by a greatest lower bound of and a least upper bound when n = . (Simplify your answers.) O C. {an} is not monotonic. The sequence is unbounded with no upper or lower bound. O D. {an) is monotonic because the sequence is nondecreasing. The sequence has a greatest lower bound of but is unbounded because it has no upper bound. (Simplify your answer.)