A Car Travels in a Flat Circle of Radius R $\degree$

A car travels in a flat circle of radius R.At a certain instant the velocity of the car is 20 m/s north,and the total acceleration of the car is 2.5 m/s² 37 $\degree$ south of west.Which of the following is correct?

A) R = 0.40 km,and the car's speed is decreasing.
B) R = 0.20 km,and the car's speed is decreasing.
C) R = 0.20 km,and the car's speed is increasing.
D) R = 0.16 km,and the car's speed is increasing.
E) R = 0.16 km,and the car's speed is decreasing.