Final answer:
Miscarriage is the condition characterized by the spontaneous and premature expulsion of the products of conception in early pregnancy.
Step-by-step explanation:
The condition described as the 'spontaneous and premature expulsion of the products of conception' is called miscarriage (option b).
Miscarriage typically occurs very early in pregnancy, usually within the first few weeks, and is the result of the fetus not developing properly. This natural termination of gestation can happen due to various factors.
It is important to note that miscarriage is different from induced abortion, which is the intentional ending of a pregnancy.