The average speed of a train is 180% of the average speed of a car. The car covers a di stance of 990 km in 15 hours. The time taken (in hours) by the train to cover the distance of 891 km is:

A

$$9\frac{1}{2}$$

B

$$7\frac{1}{2}$$

C

$$6\frac{1}{2}$$

D

$$5\frac{1}{2}$$