The correct option is D Flagellum
The sperm consists of a head, a middle piece and a tail. The head contains the nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome, which contains enzymes used for penetrating the female egg. The middle piece has a central filamentous core with many mitochondria spiralled around it, used for ATP production for the journey through the female cervix, uterus and uterine tubes. The tail or flagellum executes the lashing movements that propel the spermatocyte.