(10) A varying immediate annuity with a term of 2n years has a first payment equal to 1. Thereafter payments increase by 1 each year until they reach n at the end ofn years. Payments remain at n for year n +1 and then decrease by 1 each year, with a final payment of 1 at the end of 2n years. Derive an expression for the present value of this annuity. (c)and-T) (A)(1-T) (E) ant ) Multiple Choice: (B) and + (D) and + )