The second sentence is correct.
Use the process of elimination to get an answer for this problem.
The first sentence would not be correct because it uses 'like', usually used for comparison. Since you are not comparing two questions, it would not be appropriate.
The third sentence has 'is' before the colon, which is a implies declaration and not listing. So, again, it would not be appropriate.
The fourth and last sentence would employ a comma, or semi-colon, and not a colon so it is not properly punctuated.
The second sentence, however, lends itself to have a listed item after it, or points to the question being mentioned.