The correct option is B 1 cm (on map) = 100 m (on ground)
On the ratio scale, first take the left side of the ratio and then the right side of the ratio and multiply both by 1 cm.
Then, we have 1 cm : 10000 cm.
Note: 1 m = 100 cm
Therefore, 1 cm (on map) = 100 m (on ground).