The occurrence of more than one embryo in a seed is referred to as:

The correct answer is Option (3) → Polyembryony

In many Citrus and mango varieties, some nucellar cells around the embryo sac start dividing, protrude into the embryo sac and develop into embryos. Such an ovule then contains many embryos. The occurrence of more than one embryo in a seed is called polyembryony. Squeezing an orange seed shows several embryos of different sizes.

Option (3) Polyembryony — Correct. The occurrence of more than one embryo in a seed is referred to as polyembryony.

NCERT Extract:
Apomixis and Polyembryony – “… More often, as in many Citrus and Mango varieties some of the nucellar cells surrounding the embryo sac start dividing, protrude into the embryo sac and develop into the embryos. In such species each ovule contains many embryos. Occurrence of more than one embryo in a seed is referred to as polyembryony.”