If a man is eating fish as his food, which trophic level is occupied by him in the food chain?

Fourth

The correct answer is Option (4) → Fourth

A trophic level is the position an organism occupies in a food chain, based on what it eats and who eats it.

• Producers (1st trophic level) → e.g. Phytoplankton / plants
• Primary consumers (2nd trophic level) → e.g. Zooplankton (eat phytoplankton)
• Secondary consumers (3rd trophic level) → e.g. Small fish (eat zooplankton)
• Tertiary consumers (4th trophic level) → e.g. Humans eating big fish

In general, when humans eat fish, they usually occupy the 4th trophic level (tertiary consumer) in the food chain.