The correct option is (A) 1600 m.
Explanation:
We know distance covered = dmax = √2hR
where h is height of antenna.
i.e. d ∝ √h
∴ (d2 / d1) = √(h2 / h1)
Given: d2 = 3d1
Hence
3 = √(h2 / h1)
∴ h2 = 9h1
∴ h2 = 9 × 200
h2 = 1800 m
∴ height of tower to be increased by h2 – h1
i.e. (1800 – 200) m = 1600 m