In describing his stages of moral development, which of the following did Kohlberg argue?

a$.$ Individuals go through all of the stages and always in the same sequence though the pace may vary.

b$.$ Individuals go through the same sequence, but the pace may vary, and some individuals may never progress beyond the first few stages.

c$.$ Individuals go through some of the stages, but not necessarily in the same order, and the pace may vary.

d$.$ Individuals go through all the stages, but not necessarily in the same order, and the pace may vary.