A body is thrown vertically upwards with a velocity V1, using a time t1 to reach its maximum height and reaching the ground having elapsed a time t2. Then, it is correct to state that the body...
I. Between 0 and t1, its acceleration is positive.
II. Between t1 and t2, its speed increases.
III. It moves in the +y direction.
IV. Between t1 and t2, its acceleration is positive.

a) Only I
b) I and II
c) All
d) Only II
e) None