M starts from her home, walks 300 m south, turns right and walks 800 m, turns right and walks 450 m, turns right and walks 250 m, turns left and walks 150 m and then turns right and walks 550 m. How much distance and in which direction should she walk back to reach her home by the shortest route?

​M starts from her home, walks 300 m south,

Now, 150 m + 150 m = 300 m southward.

Thus, the correct option is (a) 300 m southward.