A train starts from station P, runs through stations Q, R, S, T and reaches station U. It stops at stations Q, R, S and T for 2 minutes, 4 minutes, 6 minutes, and 8 minutes, respectively. The distance between P and U is 50 km. What is the average speed of the train between stations P and U (in km/h), if it runs for 70 minutes between the stations, with uniform speed?

A

$$\frac{100}{6}$$

B

$$\frac{110}{3}$$

C

$$\frac{110}{4}$$

D

$$\frac{100}{3}$$