Which ball pen to use?

Use blue or black ball point pen.

I personally recommend a good blue ballpen like reynolds/mitsubisi etc..

**DM

As prescribed:

COLOR OF INK:  Blue or Blue Black

Type of Pen: Fountain pen preferred by institute.  Ball pen not expressly prohibited.

There is nothing specifically prescribed. Choose the Type and colour of pen you are comfortable with. Its too late to experiment now. Its something like a left handed batsmen should always bat as a lefty and should not change his batting style based on the bowling attack. Back your strength.

It will be better if you use dot pen either blue or black.But try to avoid GEL pen.