What happens to a spermatid to change it into a sperm cell?
meiosis occurs, making the sperm cell haploid.
the nuclei of two polar bodies fuse, making a diploid cell.
a tail is added, making the sperm a motile cell.
a membrane hardens, making the sperm a nonmotile cell.

A spermatid is changed into a sperm cell by adding a tail, making the sperm a motile cell.

Explanation:

Spermatids become sperm cells by a process known as spermiogenesis.

In this process of spermiogenesi, a tail is formed by spermatids. This tail is formed by growing of micro tubules grow into basal body. The spermatid DNA also becomes highly condensed and packaged. Further changes in the spermatids change them into spermatozoa which is non motile.

The non- motile spermatozoa are converted into motile sperm cells having capability of fertilization in the epididymis.

its C.    a tail, making the sperm a motile cell.

Explanation:

this protocol provides a detailed procedure for total protein extraction for western blot analysis from achieved samples following trizol isolation of rna.

i think its the first one