The correct option is C Potato
Starch is reserve carbohydrate of plant cells which forms simple (e.g., Maize, Pea) or compound (e.g., Rice, Oat) grains inside amyloplasts and chloroplasts. Each grain has a central point or hilum around which starch is laid as concentric (e.g., Wheat, Rice, Maize) or eccentric (e.g., Potato) shells. In each shell, there is a higher refractive index on the inner side (produced during daytime) and lower refractive index on the outer side (produced during night time). The shape is round or oval (e.g., Potato, Wheat), spindle-like (e.g., Banana) or like a dumb-bell (e.g., Euphorbia).