The difference between spermiogenesis and spermiation is:

The correct option is D In spermiogenesis spermatozoa are formed, while in spermiation spermatozoa are formed released from sertoli cells in to the cavity of seminiferous tubules
Spermatogenesis is a process by which sperms are produced inside the testis.

The spermatogonia (germ cells) undergo mitosis and differentiation to form into primary spermatocytes.

The primary spermatocyte undergoes meiosis I and forms secondary spermatocytes.

The secondary spermatocyte undergoes meiosis II and forms spermatids.

Spermiogenesis is the process by which haploid round spermatids transform into spermatozoa (sperms) which are capable of motility.

After spermiogenesis, sperm heads get embedded in the Sertoli cells and draw nourishment and finally get released.

Spermiation is the process of release of sperms from the Sertoli cells into the lumen of seminiferous tubules.