More than likely a caliper job, but don't
overlook the common possibility of a restricted rubber flex hose. As they age ,they will allow the brakes to work under the pressure of the pedal, but not let the fluid release back to the Master cyl. because there is not enough pressure in that direction. That makes the pad hang up on the rotor.
A quick test for this is to spin that wheel
after someone pumps the brake. If it is hard to turn after letting up on the pedal, open the bleeder. If it immediately frees, it will
indicate a bad hose.