Correct option (d) endocarp
Explanation:
Lemon is a hesperidium type of fruit. Epicarp of this fruit contains many oil glands. Below epicarp is present a fibrous part which fuses with epicarp, this is known as mesocarp. While endocarp projects inwards and forms distinct chambers. Many unrcellular juicy hairs are present on the inner side of endocarp which are edible parts of this frult.
