CMAT questions on Odd Sentence Out

Common link: bajra (pearl millet), barley and rice are all cereal grains, grown for their starchy grain and eaten as staple food.

Mustard is an oilseed crop, grown mainly for oil (and as a spice). It is not a cereal.

Answer: Mustard

Since the potato grows under the ground while the other three grow above the ground so the potato is the odd one out.

Hence, option (b).