gm techniques – How to handle “I investigate for ” checks

The characters enter a room, and get the general “what do you see” spiel.
One player announces that he wants to “Investigate the room for “. (Let’s say “investigate for odd books”) or the rogue says he stops the group at the threshold and wants to “investigate the room for traps or other danger”.

I can see 3 main options for how I proceed from here:

  1. Treat everything after “I investigate …” as flavour fluff, ignore it, and treat it as an entirely generic “Investigate the room” check.
  2. Treat it as a very narrow investigation and only provide information that pertains to the specified target; the character can’t notice anything that’s not specifically related to the described investigation target, even if they, say, rolled a nat 20 and would otherwise have noticed the other suspicious things nearby.
  3. Do something along the lines of treating this as a general check but with some hindrance on general targets and some benefit to the specific targets. (Say +3 on the investigation of the books, but -3 on the investigation of the room as a whole.)

#1. Seems to ignore the players role-playing and agency.

#2. Is going to end up with the players having to list out everything that could be interesting and doing tonnes of Investigation checks.

#3. Feels like the most interesting and flavour-ful way to handle it, and rewards the players for correctly guessing what’s suspicious. But is also clearly the furthest deviation from RAW.

What’s the normal way to handle this?