The correct option is D It is the longest cell
Sperm is the microscopic, elongated haploid motile gamete consisting of a large nucleus, which carries genetic information. It does not have a cell wall. The tail of sperm is long, slender and tapering structure capable of swimming. But it is the smallest cell of the body and not longest. The longest cell in the body is the neuron or nerve cell. Thus, option D is the correct answer.