Why does my 95 Honda Civic EX stall when I step on the clutch while the A/C is on?

Why does my 95 Honda Civic EX stall when I step on the clutch while the A/C is on?

Idle too low.

Bad "step up" solenoid.
Bad TPS.
Dirty throttle plate.
Vacuum leak

and possibly,

Bad compressor or other AC problem (probably not, but possible).