What is perisperm?

The correct answer is Option (1) →Remnants of nucellus.

Perisperm is a layer of nutritive tissue in the seed of certain flowering plants that are derived from the nucellus and surrounds the embryo. In seeds of some plants remnants of a nucellus is persistent. This residual, persistent nucellus is called perisperm. However, in some plants, the nucellus does not completely degenerate after fertilization, and instead, it persists as a layer of nutritive tissue around the embryo. This tissue is called perisperm. Perisperm is found in the seeds of a variety of plants, including black pepper, beet, and coffee.