A man, standing at a point X on the bank XY of a river that cannot be crossed, observes a tower to be `N alpha^(@) E` on the opposite parallel bank. He then walks 200 m along the bank to the point Y towards East, and finds the tower to be `N beta^(@) W`. From these observations, the breadth of the river will be
(Given that tan `alpha^(@) = 2` and `tan beta^(@) = 0.5`)

Options

A. 60 m
B. 70 m
C. 80 m
D. 90 m