Of the following equations, which have undergone a horizontal expansion from their original equations y=sinx and y=cosx?
I. y=2cos(3/4x)
II. y=-sin(3/2x)
III. y=3cos(5/4x)
IV. y=5sin(4/3x)
V. y=12cos(1/3x)
O II, III, IV and V
O II and IV
O II, III and IV
O I only
O I and V