Alice: Hello, can I speak to Mr. Smith, please?
Receptionist: I'm sorry, he's not available right now.
Alice: Could you tell me when he will be back?
Receptionist: I'm afraid I don't know. Would you like to leave a message?
What is Alice's main purpose for calling?
A) To leave a message for Mr. Smith.
B) To speak directly to Mr. Smith.
C) To ask about Mr. Smith's schedule.
D) To end the conversation quickly.