Light travels
a. about 300,000 km/s.
b. faster than anything we know of.
c. the same speed as other types of electromagnetic radiation.
d. all of these describe how light travels.
Actually, 'b' doesn't go far enough. Light is not only "faster than anything else we know of", we now know that it's impossible for anything with mass to ever hit that speed, so we can just quit looking.