Which of the following is not a seed?

Gram and chickpea are examples of seeds. Another name for chickpea is Bengal gram. 

Chickpeas have high protein value. Gram or chana has fibre, minerals and vitamins. 

A lemon is not a seed. It is an example of fruits. Seeds are present inside the lemon. Around five-twelve seeds can be found inside a lemon. 

There the correct answer is option  (C).