Mr. A lives at origin on the Cartesian plane and has his office at `(4,5)` His friend lives at `(2,3)` on the same plane. Mrs. A can go to his office travelling one block at a time either in the `+y or +x` direction. If all possible paths are equally likely then the probability that Mr. A passed his friends house is (shortest path for any event must be considere (a) `1/2` (b) `10/21` (c) `1/4` (d) `11/21`