Bergen/Tromso/Lofoten
 

Which of the places(Bergen/Tromso/Lofoten) should I choose if I only have 2 days 1 night from 12th to 13th December? I am departing from Oslo to the above mentioned cities.

Lofoten isn't a city, it is an archipelago, and as such needs more than one night.

I assume you are flying? Going by train would take most of your two days.

Bergen is the second city of Norway and easily has enough to fill your time.

Tromsø is smaller, more compact and is probably better suited to such a short time frame.

It depends somewhat on what you are interested in seeing/doing.

Bergen I'd say. Though it's a close tie with Tromsø

Bergen with its Christmas market!

The sun doesn't rise in Tromsø at this time, just some hours of blue twilight. People travel to Tromsø in winter for the Northern Lights, but you need more than one night to have a reasonable chance of catching them.
Unless you are prepared to spend a reasonable amount of time in one of these places I would just stay in Oslo.