**Core Concept**
A complete mole, also known as a complete hydatidiform mole, is a type of gestational trophoblastic disease characterized by abnormal trophoblastic proliferation and villous hydropic degeneration. This condition occurs when a complete fertilization of an egg without fertilization of the nucleus, resulting in a diploid but genetically abnormal fetus.

**Why the Correct Answer is Right**
Option b) Trophoblastic proliferation is a hallmark of complete molar pregnancies, where the trophoblastic cells exhibit excessive growth and differentiation. This leads to the formation of abnormal villi and the characteristic hydropic degeneration of the villous stroma. The correct answer also includes option c) Hydropic degeneration, which is a characteristic feature of complete molar pregnancies due to the abnormal villous development and excessive trophoblastic proliferation.

**Why Each Wrong Option is Incorrect**
**Option A:** Complete mole seen in human only - This statement is incorrect as complete moles can also occur in other species, such as cattle and sheep. However, the question is referring to human pathology.
**Option D:** Villus pattern absent - This statement is incorrect as the villus pattern is actually abnormal and hydropically degenerated in complete moles.

**Clinical Pearl / High-Yield Fact**
It's essential to note that complete moles are often associated with elevated hCG levels, which can lead to complications such as hyperemesis gravidarum and preeclampsia. Furthermore, complete moles have a higher risk of developing into gestational trophoblastic neoplasia (GTN) compared to partial moles.

**✓ Correct Answer: B. bc**