The seeds of plants contain
a. ovules.
b. embryos.
c. sepals.
d. both
a. and
b.

The correct answer is- b. embryos.

A seed is tiny, tough plant part ( that contains tiny plant called embryo), surrounded by a protective covering and gives a complete plant.

The seed formation in an essential step in the reproduction of seed plants ( such  gymnosperm and angiosperm).

Ovule present within an ovary gives rise to seeds when fertilized by pollen grain. The embryo is developed from the zygote and the seed coat is formed by the integuments in the ovule.

Thus, plant seeds contain embryo is the right answer.