In the following question, a phrasal verb is given in bold, it is then followed by three sentences which has used the given phrasal verb. Choose the best set of alternatives from the five options given below which has correctly used the given phrasal verb without altering the meaning of the sentence.

Check out

(A) Before you leave the hotel, don’t forget to check out at the reception desk.
(B) I’m going to the library to check out some books for my research paper.
(C) You should check out that new restaurant downtown; I’ve heard great things about it.

The correct answer is All A, B, C.

Let's analyze the meaning of the phrasal verb "Check out" and how it is used in each sentence:

1. Meaning 1: To settle one's bill and leave a hotel or other lodging.
In sentence (A): "Before you leave the hotel, don’t forget to check out at the reception desk."
Here, "check out" is used correctly to mean formally leaving and paying the bill at a hotel reception desk.

2. Meaning 2: To borrow something (like a book) from a library or official system.
In sentence (B): "I’m going to the library to check out some books for my research paper."
Here, "check out" is used correctly to mean borrowing books from a library for a period of time.

3. Meaning 3: To examine, inspect, or try something interesting.
In sentence (C): "You should check out that new restaurant downtown; I’ve heard great things about it."
Here, "check out" is used correctly as an informal suggestion to go visit or try a new place.

Since the phrasal verb "check out" is used correctly according to its standard English meanings in all three sentences (A, B, and C), the option All A, B, C is the correct choice.