She went to her boss and apologised ______ being so slow.

• A. For
• B. In
• C. On
• D. At

Answer: (A)

The main idea is how we explain what we’re apologizing for. After the verb apologise, we commonly use for + the -ing form to state the reason for the apology. In this sentence, being so slow is the reason she’s apologising, so the natural form is for being so slow. The pattern is apologise for + [-ing], which neatly expresses regret about a specific action or situation. If you wanted to mention who is receiving the apology, you’d add to someone: apologize to your boss for being so slow. The other prepositions don’t link the apology to its reason in this context.