Dear Ruhesh,

There is no restriction on using black pen for headings and blue pens for answers as such, but it won’t fetch extra marks for writing heading in black pen. I am worried that you might run short of time during examination by doing that. Rather then writing headings with black pen ; I would suggest you to write everything with blue pen and then underline the headings / key words using pencil and scale. For better presentation , you can go for drawing lines with pencil after every answer ( do this only after completing your entire paper and if you have time left ).

Hope it helps you.

All the best!