Data Sufficiency

Two missiles are launched simultaneously. Missile 1 launches at a speed of x miles per hour, increasing its speed by a factor of √x every 10 minutes (so that after 10 minutes its speed is x(√x), after 20 minutes its speed is x(√x)(√x), and so forth. Missile 2 launches at a speed of y miles per hour, doubling its speed every 10 minutes. After 1 hour, is the speed of Missile 1 greater than that of Missile 2?

1)x=√x
2)x>8

[spoiler]I marked A Because i thought for x=√x , should be 1 ,
but the answer is C don't know why? [/spoiler]