Q10:
A set of numbers has the property that for any number t in the set, t + 2 is in the set. If –1 is in the set, which of the following must also be in the set?
I. -3
II. 1
III. 5
A. I only
B. II only
C. I and II only
D. II and III only
E. I, II, and III
Answer:
According to the key answers, “D” shall be the right answer, but I think it shall be C.
Anyone can explain? | 
