A boy starts from point A and walks 7 km towards West; turns left and walks 5 km and turns another left and walks 7 km. He then walks 2 km towards North; turns left and walks 3 km; turns right and walks 3 km. He then finally walks 9 km after turning right and reaches B. How far is A from B?
1
6 km
2
10 km
3
4 km
4
8 km