Answer:
Step-by-step explanation:
1 is not the answer. Some sort of punctuation is needed after skill. The way it is written is a run on.
2. Of the answers given, this answer is the best choice. A full colon would be even better.
3. The comma is misplaced in three. Leave out the comma and this answer would be correct.
4. Again the comma is too much. So is the and really.
I would choose B but I think a colon works better.