Number series
What is the missing number in the series: 2, 6, 12, ....., 42?
I. 18
II. 42
III. 24
IV. 36
Question: 以下哪项是正确的？
Options:
A. 仅 IV, B. 非 III, C. IV 为真, D. 仅 II, E. 仅 III
Answer: A, B, C