## **Core Concept**
The underlying principle being tested here involves the physiological changes during pregnancy and how they impact the cardiovascular system, as well as the signs that may indicate underlying heart disease. Pregnancy induces significant cardiovascular changes, including increased blood volume, heart rate, and cardiac output. These changes can unmask or exacerbate pre-existing heart conditions.

## **Why the Correct Answer is Right**
The correct answer includes signs that are concerning for heart disease in pregnancy.
- **Diastolic murmur (a)**: A diastolic murmur is always abnormal and can indicate conditions such as mitral stenosis or aortic regurgitation.
- **Dyspnea on exertion (d)**: While common in pregnancy due to increased demand and respiratory changes, when severe or in conjunction with other symptoms, it can indicate heart disease.
- **Nervousness or syncope on exertion (e)**: These symptoms suggest a possible inability to increase cardiac output appropriately with exercise, indicative of heart disease.

## **Why Each Wrong Option is Incorrect**
- **Option B: Systolic murmur (b)**: While a new systolic murmur can be concerning, systolic murmurs are common in pregnancy due to increased cardiac output. However, characteristics such as intensity, timing, and presence of other symptoms help determine its significance.
- **Option C: Tachycardia (c)**: Tachycardia is a normal finding in pregnancy due to increased sympathetic tone and blood volume expansion. A heart rate increase of 10-15 bpm is typical.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that physiological changes in pregnancy can mimic symptoms of heart disease. However, certain symptoms like **diastolic murmurs**, **severe dyspnea**, **syncope**, or **chest pain** on exertion are red flags for underlying cardiac issues. Always consider the context and potential impact of pregnancy on the cardiovascular system.

## **Correct Answer:** D. a, d, e.