Point R is 10 metres north of point A. Point K is exactly in the middle of the points R and A. Point N is 7 metres east of point A. Point M is 7 metres east of point K. Point S is 6 metres north of point M. What is the distance between points S and N?

A

13 metres

B

16 metres

C

11 metres

D

12 metres

E

None of these