I just installed the keyless entry/alarm system a few months ago in my 1999 Integra. I'm not sure what the option button does, but I can list what the Operating Instructions manual says. Upon testing the OPTION button just a few minutes ago, I found mine does nothing. I have the "electrically driven unlock system", but I'm not sure what the instructions below mean by "electrically driven unlock system using accessories for the glass hatch or trunk". Mine only works for switching the arm and disarm beep on/off. My hatch will unlock when I press the unlock button on the remote twice, but then so do all my doors.

Controls and Functions

3. OPTION - When the OPTION button is pressed and held for more than one second, the hatch (or trunk) will unlock. (Functional only on the vehicles equipped with electrically driven unlock system using accessories for the glass hatch or trunk. For details, contact your ACURA dealer.)

4. OPTION Button - When pressed and held simultaneously with the LOCK button for more than 1 second, the confirmation "BEEP" feature is switched between on and off. The remote control indicator LED will flash once when the confirmation "BEEP" is turned on, and flash twice when the confirmation "BEEP" is turned off.

Not sure this will be of any help...

JD