İngilizce telefon konuşmaları (Telephone conversations) Test 1

You are taking a message for a colleague. The caller says:
"Could you please let her know that Mr. Jensen called regarding the merger documents, and it's urgent?"
Which information is NOT essential to include in the message?

A) The caller's name (Mr. Jensen)
B) The topic (merger documents)
C) The urgency
D) The caller's phone number (if already known to your colleague)