A man starts from point ‘O’, travels 20 km towards east to reach point ‘A’, turns right and travels 10 km to reach point ‘B’, turns right and travels 9 km to reach point ‘C’, turns right and travels 5 km to reach point ‘D’, turns left and travels 12 km to reach point ‘E’ and then turns right and travels 6 km to reach point ‘F’. What is the shortest distance between point ‘E’ and point ‘C’?

A

$$13 km$$

B

$$\sqrt{2}$$

C

$$\sqrt{20}$$

D

$$\sqrt{145}$$