Knowledge

During work, Santa and Banta were chatting:

Santa: Banta, I've been attending night classes for 5 months now and I have an exam next week.
Banta: oh!

Santa: For example, do you know who is Graham Bell?
Banta: No
Raman: He's the inventor of the phone in 1876; if you take night Courses you would know this.

The next day, the same discussion took place:
Santa: Do you know who Alexander Dumas is?
Banta: No
Santa: He's the author of "The 3 Musketeers", if you take night courses, you would know this.

The next day, once again:
Santa: And do you know who Jean Jacques Rousseau is?
Banta: No
Santa: He's the author of "Confessions", if you take night courses, you would know this.

This time, Narayan got irritated and said: And you, do you know who is Ghanta Singh is?
Santa: No
Banta: He's the guy roaming with your wife!! If you stop night courses, you would know this.