A: What was John doing here?

B:He wanted to ask   c)for more information (correct!)

   a)About a research (about research I was doing, some research Fred had done, about the research we shall be conducting, etc.) 

   b)for a new equipment (some new equipment, a piece of new equipment, etc.)

   d)about my travel (about my travels, about my trip, etc.)

You can't count research or equipment.  It's awkward to use them alone, unmodified. 

"Travels", surprisingly, seldom means "trips" but rather "stories about my trips/traveling".  "Travel" can be used in the singular, but you need more context.  "He wanted to ask about my travel through Mexico."/"He wanted to ask about my travels through Mexico."  It's acceptable to say "He wanted to ask about my travels" and "He wanted to ask about my trip."