The z-transform X(z) of x(k)=aK K=0,1,2,.... and x(k)=0 K<0 has:

Select one: a. One pole at z=0 and one zero at z=a b. One pole at z=a and one zero at z=a c. One pole at z=a and one zero at z=0 d. One pole and one zero at z=0