reactions

In this case,

The NO₂⁺ will go to the para position w.r.t OH and meta position wrt COOH as there will be a reinforcement and also that position is sterically less hindered.

So, ans shud be (a)

Pls correct me if i m wrong!

yes ans is [a].

remember,,,

wenever there's a withdrawing group, and a donating group in a single ring...
and u need to attach an electrophile,
the points which are favourable are :
1) o,p to the donating group.
2) meta to the withdrawing group.

also remember,,,

NEVER is an electrophile attached 'in between' two grups which are meta to each other...

i hope this wil help. :)