Need help with this, need the formula. and not excel please

Find the present value of 20 annual payments of $2,500 per annum where the first payment is made 5 years from now. 50 there are 20 annual payments from t=5 to t=24 inclusive. The discount rate is 5% pa. The present value of these payments is: Select one. a. $41,135,12 b. $28,987.81 c. $25,631.73 d. 515,503,4 e. $1,281,59 The correct answer is $25,631,73