A group of scientists have been sent on an expedition to test the soil in the Allegheny Mountains. They need to collect samples from nine sites. The route for the expedition is shown in the image. The group starts at P and works its way around to Q, R, S, T, U, V, W, and X, in that order, before returning to P. What is the length of the route? A.

50 units

B.

52 units

C.

55 units

D.

58 units

E.

60 units