assume the graph of a function of the form y=acros(k(x-b)) is given below. which of the following are possible values for a,k and b? A. a=2,k=4, and b=pi/4 B. a=4,k=2,and b=pi/4 C. a=4, k=2, and b= -pi/4 D. a=4, k=1/2, and b=-pi/4