A delivery drone needs to travel from its base station at (0,0) to a drop-off point located 3 units east and 4 units north. The drone can only move one unit east or one unit north at a time. There is a no-fly zone covering the intersection at (1,3). How many distinct paths can the drone take from (0,0) to (3,4) while avoiding the point (1,3)?
21
22
23
24
25