Answer:
The effective rate of return can be calculated using formula given below.
ER = (1+I)^n-1
where i is nominal rate and n is number of payment in an year. So
(a) annually
ER = (1+9%)^1 -1= 9% (same)
(b) semiannually
ER = (1+9%/2)^2-1 = 9.2%
(c) quarterly
ER = (1+9%/4)^4-1 = 9.31%
(d) monthly
ER = (1+9%/12)^12-1 = 9.34%