Select the letter that can replace the question mark (?) in the following series. J, M, P, ?, V, Y

R O S T

S

Pattern followed is : Add 3 in each next number . J + 3 = M , M + 3 = P , P + 3 = S , S + 3 = V , V + 3 = Y S fits well in series to follow the pattern . Ans = S