In a 1200 m race, bike A beats bike B by 100 m. Bike B beats bike C by 100 m in a 600 m race. If bike A beats bike C by 30 sec in a 720 m race, then what is the speed of bike C?

A

$$\frac{17}{3}$$ m/sec

B

$$\frac{26}{9}$$ m/sec

C

$$\frac{17}{9}$$ m/sec

D

$$\frac{26}{3}$$ m/sec