Mullet fish are known to jump out of the water when being pursued by predators. The height in inches of one mullet fish can be described by the function f (x) = 2cos2x − 1, where x represents the time in seconds. Another mullet fish's height from the water level can be represented by the equation g(x) = −sin x. At which values on the interval [0, 2π) will the two fish be at the same height above the water?

A: pi/2
B: { 7pi/6 and 11pi/6 }
C: { pi/2, 7pi/6, 11pi/6 }