Final answer:
The male in humans is referred to as the heterogametic sex because they produce gametes with either X or Y chromosomes, unlike females who produce gametes all containing an X chromosome.
Step-by-step explanation:
In humans, the male is the heterogametic sex. This means that males produce two different types of gametes regarding the sex chromosomes they carry. In contrast, females are the homogametic sex, producing gametes that all contain the same type of sex chromosome.
In mammals, the sex determination system is such that females have two X chromosomes (XX), making them homogametic, while males have one X and one Y chromosome (XY), making them heterogametic. Therefore, the correct answer to the question is B) heterogametic.