Human spermatozoa:
a. wiil contain either a y chromosome or a x chromosome but not both.
b. contain 23 chromosomes
c. reach maturity in the seminal vesicles
d. contain enzymes in their heads which facilitate penetration of the ovum.
e. are produced at a more rapid rate than the oocyte

a. will contain either a Y chromosome or a X chromosome but not both.

Explanation:

There are two types of human spermatozoa, the x-chromosome carriers (female) and the y-chromosome carriers (male). However, a sperm will never have both chromosomes at once.

Thus, if the egg is fertilized by an x-chromosome, the result will be a girl. Otherwise, if fertilized by a y-chromosome, it will be a boy.

The sperm is formed by a head and tail. In the flat egg-shaped head we have the nucleus that houses the genetic material. This region is responsible for the transmission of paternal hereditary characters. The tail (or flagellum) is divided into three parts: intermediate part, main part and end piece. It facilitates the locomotion of the male sexual gamete to the egg.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.