Concerning Fannie Mae-sponsored Mortgage Backed Securities (MBS): Identify which of the following statements is correct

a) The coupon rate on pass-through MBS sold to investors is always higher than the average coupon on the individual mortgages making up the pool

b) The coupon rate on pass-through MBS sold to investors is always set equal to the average coupon on the individual mortgages making up the pool

c) The coupon rate on pass-through MBS sold to investors is always lower than the average coupon on the individual mortgages making up the pool

d) The coupon rate on pass-through MBS sold to investors is sometimes higher, sometimes equal to, and sometimes lower than the average coupon on the individual mortgages making up the pool