Enthuware

the question says the size is cA[2][3], not index cA[2][3].
So the given answer is not right.

No, the problem statement does not say "size is cA[2][3]". It says, "...with a size such that cA[2][3] refers to a valid element". Please observe the "such that cA[2][3] refers to a valid element" part.
The problem statement is quite clear on what it is saying. You have to create the array such that cA[2][3] refers to a valid element.

Hi, why is this question marked with a "very tough" level? Should not it be easy at most?

Toughness level is decided by the author and can be a bit subjective. So if you think this question is not too tough, that's fine.