What is the genetic nature of apomictic embryos?

Diploid

The genetic nature of apomictic embryos is diploid. So the answer is (a).

Apomixis is a type of asexual reproduction in plants that does not involve fertilization. Apomictic embryos are formed from unfertilized eggs, or from other cells of the ovule, such as the nucellus or integuments.

Apomictic embryos are the embryos which are formed without the process of fertilization and they are directly developed from the diploid egg present in the embryo sac. Sometimes there will be no proper mitotic and meiotic divisions in the embryo sac which leads to the formation of a diploid egg. This diploid egg directly develops into a new organism. As there is no fertilization, the newly formed embryo is genetically similar to the parent and otherwise also known as the clone.