Endosperm is completely consumed by the developing embryo in
A. Pea and groundnut
B. Maize and castor
C. Castor and groundnut
D. Maize and pea

Hint: A seed consists of an embryonic axis, cotyledons, and a protective covering called seed coat. The seeds that have endosperm at maturity are called albuminous seeds. On the other hand, the seeds that lack the endosperm at maturity are called ex-albuminous seeds.

Complete step by step answer: Angiosperms (flowering plants) exhibit double fertilization during which one haploid male gamete fertilizes the egg cell to form a diploid zygote while the other fuses with two polar nuclei of the central cell to form the primary endosperm nucleus. The polar nuclei and male gamete are haploid. Therefore, the primary endosperm nucleus developed from the fusion of two polar nuclei, and one male gamete is triploid.
The zygote develops into the embryo by repetitive mitotic divisions. The primary endosperm nucleus undergoes repetitive nuclear divisions to form the free nuclear endosperm. Cell wall formation transforms the free nuclear endosperm into the cellular endosperm. The cells of the endosperm are rich in nutrients and provide nutrition to the developing embryo.
The endosperm is present as the triploid tissue in the seeds of flowering plants. During embryonic development, embryos of some seeds consume a part of endosperm and the rest is retained in the mature seeds. For example, seeds of castor, maize and coconut have endosperm at maturity.
On the other hand, embryos of some seeds such as groundnut, pea, and beans consume the whole endosperm during development. These seeds lack the endosperm at maturity.
So, the correct answer is option A. Pea and groundnut.

Note: Endosperm is required for the nutrition of the developing embryo. Therefore, it is developed before the development of the embryo. Since the endosperm is derived from the triploid primary endosperm nucleus, it is triploid.