Answer:
Warning: This cabinet contains dangerous electrical equipment.
Explanation:
The first two are incorrect because the comma is in the wrong place and in the other there is no punctuation. Semicolons are usually used to have an ordered list or a stop.
D, or 4, is the right answer.
The first two are incorrect because they are missing the colon.
Number 3 uses a semicolon, which is only used to order a stop or pause.
4 contains the right punctuation.
