Rahul has cold. He can't taste the flavour of his favourite food. This is because

Correct option is C

The correct answer is Cold affects his sense of smell.
Cold affects the sense of smell, which affects the ability to taste food. The taste buds themselves are not affected by the cold, but rather the signals they receive from the nose are disrupted. The papillae, which contain the taste buds, are still sensitive but not receive accurate information from the nose. This is why food may taste bland or different when someone has a cold. Papillae are small bumps on the tongue that contain taste buds and help to distinguish different flavors.