Answer: C. Embryo,seed,fruit
An embryo is an initial stage of development of a eukaryotic multicellular organism. In general, the organisms that reproduce sexually, it develops from specialized diploid cell called as zygote, that forms by the fertilization of the female and male gametes. Each seed contains single to numerous embryos. A seed is a precursor tissue for the leaves, stems and roots. The seed is enclosed by a collection of fleshy tissues called as fruit.
On the basis of simplicity and size, the terms can be listed from smallest to largest as embryo,seed, and fruit.