Three trains moving with speed 45 kmph, 60kmph and 75 kmph respectively took $$t_1, t_2$$ and $$t_3$$ hours to travel $$x, \frac{5x}{4}$$ and $$\frac{3x}{2}$$ kilometers. Then $$t_1 : t_2 : t_3 = $$

A

8:7:6

B

85:75:64

C

80:72:64

D

80:75:72