Could you please tell the process behind tge answer, step by step? thanks!

SOA/CAS Course 1 November 2000#18 Due to decreasing business, the amount an insurer expects to pay for claims will decrease at a constant rate of 5% per month indefinitely. This month the insurer paid 1000 in claims. What is the insurer's total expected amount of claims to be paid over the 30 -month period that began this month? (A) 13,922 (B) 14,707 (C) 14,922 (D) 15,707 (E) 15,922