The correct punctuation in the following sentence is () A. The classroom layout is simple, and only three slogans are hung on the wall: "Persistence is the key to learning".

The period "If you see a question somewhere, you can enter it" after item A should be changed to a comma and placed outside quotation marks. Delete the exclamation point in item B, the semicolon in item C should be changed to a comma, and the question mark should be changed to a period.