What is considered a complete mole?

A complete mole, or hydatidiform mole, is characterized by the absence of any normal fetal tissue. In this situation, the ovum is typically inactive or lacking specific genetic material, and instead, it is completely replaced by paternal genetic material, usually resulting from the fertilization of an empty egg by a sperm that duplicates its chromosomes. This leads to the development of abnormal placental tissue.

While a complete mole has no viable fetus (which aligns with option C), it is crucial to emphasize that this condition can occur when the embryo conception leads only to a mass of abnormal tissue rather than any normal fetal development. The absence of a fetus is a defining feature, distinguishing a complete mole from other types of moles, such as partial moles, which may allow for some abnormal fetal structures but do not have the same level of placental proliferation.

The other choices describe scenarios inconsistent with the definition of a complete mole. The presence of a healthy fetus would indicate normal embryonic development, which contradicts the concept of a complete mole. Fertilization without ovum activation normally would not trigger development into any mole. Lastly, partial development of fetuses would also imply some degree of normal embryonic activity, something that is not present in a complete mole