A、Before 6:00 p. m. B、After 6:00 p. m. C、Anytime that day. D、Anytime. C根据He can reach me…anytime today on my mobile. 可知, 可以在当天任何

W: Good afternoon. ABC company. May I help you?
M: Yes. may I speak to Mr. James Potter. please?
W: I’m afraid Mr. James Potter isn’t available right now. Would you like to leave a message?
M: This is Martin Richard with Sun Electronics. It’s very important that he returns my call this afternoon.  
W: Does he have your office number and your mobile phone number?
M: I think so. but let me give them to you again.  
W: Okay.  
M: My office number is 714-888-3765; my cell phone number is 909-333-8739. He can reach me at my office number before 6:00 p. m. or anytime today on my mobile.  
W: Very well. I’ll give him your message as soon as he returns to the office.
At what time can Mr. James Potter call Martin Richard on his mobile?
Who might be the person that has answered the phone call?
What can be learned from the telephone conversation you’ve just heard?