Rahman went from his office to the district headquarters. He started his journey facing West. First, he went 20 km straight; then he turned to his left and went 9 km; finally, he turned right and went 20 km to reach the district headquarters.
What is the shortest distance between Ftahman's office and the district headquarters?

A

24.5 km

B

49 km

C

41 km

D

34.5 km