Alphabet series
What is the missing Alphabet in the series: W, S, O, K, ?
I. C
II. F
III. J
IV. None of these

Question: 以下哪项是正确的？
Options:
A. 非 I, B. 以上各项均不成立, C. II 或 I, D. IV 或 I, E. I 或 II
Answer: A
D
True statement: IV