The correct option is C are modified stem of the plant
True fruits are the structures that develop from the ovaries of the flowering plants and contain seeds.
Vegetables are any edible plant part such as roots, leaves, stems, etc but don’t contain seeds.
Potatoes are not considered fruits because they are modified underground stems of the plant. They represent an underground stem modification called a tuber. They don’t develop from the flower. They don’t contain seeds.
True fruits develop from mature ovaries. E.g:- peas, grapes, mango, coconut, chillies.
False fruit develops from parts of a flower other than the ovary. E.g:- apple (the fleshy fruit is not the ovary but the modified thalamus which is the thickened part of the stem which holds the flower), pear.
Ground beetroots are modified roots of the plants.