Three:
One to write the light bulb removal program,
one to write the light bulb insertion program, and
one to act as a light bulb administrator to make sure nobody else tries to change the light bulb at the same time.
or
His son, because he's a little Bigger!
or
If Trump gets Alzheimers his IQ will go up.
or
Nice belt!
or
The barman says "Sorry we don't serve food in here"
or