The correct option is C The anterior portion of the head is covered by a cap-like structure called axoneme
The sperm is divided into head, neck, middle piece, and tail. All of these are covered by an envelope of the plasma membrane. The head of the sperm includes an elongated haploid nucleus. Its anterior part is enclosed by a cap-like structure called the acrosome, which contains hydrolytic enzymes that help the sperm to penetrate the egg at the time of fertilisation. The middle piece of sperm has many mitochondria, which generate energy for the movement of the tail and hence helps in the movement of sperms for fertilization.
An axoneme is a cytoskeletal formation based on microtubules and linker proteins that constitutes the center of a cilium or flagellum.