Why Can't Masters and Johnson's Model of Sexual Response Be

Why can't Masters and Johnson's model of sexual response be generalized to the whole population?

A) The participants in their research were those who had never experienced orgasms before,thus excluding a large section of the population.
B) All participants in their research were selected for their high and consistent levels of sexual desires,which is not representative of the population.
C) The participants in their research were all male,and thus excluded the relevant experiences of half the population.
D) The participants in their research were all female,and thus excluded the relevant experiences of half the population.