Which Method Did Ole Rømer Use to Show That Light

Which method did Ole Rømer use to show that light did NOT travel at infinite speed?

A) Rømer observed that eclipses of Jupiter's satellites by the planet appeared to occur later, when Earth was farther away from Jupiter, because of the travel time for light over the extra distance.
B) Rømer measured a time delay between the instant that he sent a flash of light to a mirror on a distant hill and the return of the flash after reflection.
C) Rømer carried out a laboratory experiment in which a light beam was sent through an opaque, rotating disk with holes in it and reflected from a distant mirror, where the returning beam did not return through the same hole from which it left because of the travel time for light.
D) Rømer measured a 2-second delay between the time of the outgoing pulse of light sent from Earth to the Moon and the time of the returning light pulse after reflection from the Moon.