In following alphabet series , one term missing as shown by question mark . Choose missing term from options.
Z, S, W, O, T, K, Q, G, ?
The given sequence consists of two series :
I. Z, W, T, V, Q, ? in which each letter is moved three steps backward to obtain the next term.
II. S, O, K, G in which each letter is moved four steps backward to obtain the next term.