Determine the total surface area of a hemisphere closed at bottom. Radius of the hemisphere is 25 unit.

Answer: Option A

Total surface area (TSA) of hemisphere = 3πr²
Radius of hemisphere = $$\sqrt{\frac{25}{\pi }}$$
So, TSA = 3 × π × $${\left(\sqrt{\frac{25}{\pi }}\right)}^2$$
= 75 unit²