Raven, Omega, and Red Knight are trying to earn battle stars in physics class by solving energy problems. All three have the same mass. Raven runs up the stairs in 4 seconds, Omega skips up the stairs in 6 seconds, and Red Knight walks up the stairs in 15 seconds. Which skin has the greatest power?
a) red knight
b) they're all the same
c)raven
d)omega