**Core Concept:**
Pregnancy is associated with various physiological changes that can affect the size of certain tumors. These changes are mainly due to hormonal alterations and increased blood volume.

**Why the Correct Answer is Right:**
In this question, we are considering various types of tumors and assessing whether they grow in size during pregnancy. Option D (Rhabdomyosarcoma) is not commonly known to increase in size during pregnancy. This is because rhabdomyosarcoma is a malignant tumor originating from skeletal muscle cells, and its growth is typically unrelated to hormonal changes and physiological adaptations that occur during pregnancy.

**Why Each Wrong Option is Incorrect:**

A. **Hodgkin's lymphoma (Option A)**: While Hodgkin's lymphoma can affect pregnant patients, its growth is not typically affected by pregnancy hormones. It is a malignant lymphoproliferative disorder characterized by the presence of Reed-Sternberg cells.

B. **Benign tumors (Option B)**: Most benign tumors, including hemangiomas and lipomas, can increase in size during pregnancy due to hormonal changes and vasodilation. However, this answer is incorrect because rhabdomyosarcoma is not a benign tumor.

C. **Malignant tumors (Option C)**: Some malignant tumors can increase in size during pregnancy, such as breast cancer and some types of sarcomas. However, this answer is incorrect because rhabdomyosarcoma is a specific type of sarcoma that does not follow the same hormonal changes as other sarcomas or breast cancer.

**Clinical Pearl / High-Yield Fact:**

A clinical pearl to remember is that benign tumors are more likely to increase in size during pregnancy due to hormonal changes and vasodilation. In contrast, malignant tumors can exhibit variable behavior regarding growth during pregnancy, but rhabdomyosarcoma is an example of a malignant tumor that does not follow the typical hormonal changes observed in other malignancies or benign lesions.

**Correct Answer:** D. Rhabdomyosarcoma

The correct answer is D, rhabdomyosarcoma, as it is a malignant tumor that does not commonly increase in size during pregnancy due to its unique pathophysiology and hormonal insensitivity. Rhabdomyosarcoma is a malignant tumor arising from primitive mesenchymal cells with skeletal muscle differentiation. Unlike other tumors that can experience hormonal changes and vasodilation, rhabdomyosarcoma does not follow these changes, making it less likely to increase in size during pregnancy.