__A__ enzyme is used to remove clots from the blood vessels of patients who have undergone __B__ leading to heart attack.

Options

A. A - Streptokinase, B - Myocardial infarction
B. A - Lipases, B - Arteriosclerosis
C. A - Proteases, B - Myocardial infarction
D. A - Pectinases, B - Atherosclerosis

Answer

To solve the question, we need to identify the correct enzyme and the medical condition associated with it.

### Step-by-Step Solution:

1. **Identify the Enzyme**: The question asks for an enzyme that is used to remove clots from blood vessels. The enzyme known for this function is **streptokinase**. It is often referred to as a "clot buster" because it helps dissolve blood clots.

2. **Identify the Condition**: The question also refers to a medical condition that leads to a heart attack. The condition associated with blood clots in the heart is called **myocardial infarction**. This is a serious condition where blood flow to the heart is blocked, often by a clot.

3. **Combine the Answers**: Therefore, the complete answer to the question is:
- The enzyme used is **streptokinase** (for __A__).
- The condition leading to heart attack is **myocardial infarction** (for __B__).

### Final Answer:
A: streptokinase
B: myocardial infarction

---