Identify the correct sentence (punctuation).

The correct sentence is “Don’t be late.” This option correctly applies standard English punctuation rules for direct speech and contractions.

• The entire spoken phrase is enclosed in double quotation marks.
• The apostrophe in 'Don’t' correctly indicates the contraction of 'Do not'.
• The period, which is the end punctuation for the sentence, is placed inside the closing quotation mark, as is standard practice in American English.

The distractor 'Don’t to be late' is grammatically incorrect. 'Dont be late.' lacks both the necessary apostrophe for the contraction and the quotation marks for direct speech. Therefore, 'None of these' is also incorrect.