Endosperm, a product of double fertilisation in angiosperms is absent in the seeds of

(a) Coconut (b) Orchids (c) Maize (d) Castor

(b) Orchid seed is a non-endospermic seed, i.e., endosperm is absent in it.

Endosperm is a nourishing tissue present in the seed which nourishes the developing embryo. In orchid seed endosperm is absent because it is used up during the time of seed development.

Nourishment for germinating seed is provided by the food material present in cotyledons.

Rate of the options are examples of endospermic seeds.