Type of fruit in Citrus spp. is

Answer: Option D

Type of fruit in Citrus spp. is Hesperidium.
A hesperidium (plural hesperidia) is a modified berry with a tough, leathery rind. The outer ovary wall becomes the thick spongy layer of the rind, while the inner ovary wall becomes very juicy with several seeds. The peel contains volatile oil glands in pits.
Oranges, lemons, limes and grapefruit are all common examples of hesperidia.