consider a perpetuity with a coupon of 100. Imagine that the perpetuity is purchased at time t when the market interest rate is equal to 5%. Furthermore, imagine that the coupon income is taxed at 40% and that capital gains are taxed at 20%. What is the after tax rate of return if the perpetuity is sold at time t+1 when the market interest rate continues to be equal to 5%?

A)0%

B)2%

C)5%

D) None of the above

math and explanation please! Thank you.