Suggest a 5x10 grid divided up in squares of dimension 1 unit by 1 unit. Let A denote the lower left hand corner and B denote upper right hand corner. Any shortest path from A to B will be of length 15. How many such paths are there ?
A. C(10,5)
B. C(15,5)
C. P(10,5)
D. P(15,5)