Dear Student,
The sperm basically consists of three parts: Head, Tail and Middle piece. So, option (a) is correct: three.
 

The sperm consists of a head, middle piece, and a tail.

• The head contains a nucleus, containing the chromosomal material.

• The middle piece has many mitochondria to provide energy for the movement of the tail.

• The tail facilitates the movement of the sperm into the female body.
  
  Regards