Suppose function f is defined so that f(0)=1 and its derivative f' is given by f'(x)=esinx. Which of the following statements are true?
A) f(x) is always increasing.
B) f(x) has a minimum at x=0.
C) f(x) has a maximum at x=0.
D) f(x) is always concave up.
E) f(x) is periodic with period 2π.