The sound of lubb is produced during closure of

Options

A. Bicuspide valve
B. Tricuspid valve
C. Semilunar valves
D. both (1) and (2)

Answer

### Step-by-Step Solution:

1. **Understanding Heart Sounds**: The heart produces two main sounds during the cardiac cycle, commonly referred to as "lubb" and "dub." These sounds are associated with the closing of specific heart valves.

2. **Identifying the Sounds**:
- The first sound, "lubb," is produced during the closure of the atrioventricular (AV) valves.
- The second sound, "dub," is produced during the closure of the semilunar valves.

3. **Identifying the Atrioventricular Valves**: The atrioventricular valves consist of:
- The **bicuspid valve** (also known as the mitral valve), which is located between the left atrium and left ventricle.
- The **tricuspid valve**, which is located between the right atrium and right ventricle.

4. **Conclusion**: Since the "lubb" sound is produced by the closure of both the bicuspid and tricuspid valves, the correct answer to the question is that the sound of "lubb" is produced during the closure of both the bicuspid and tricuspid valves.

5. **Final Answer**: Therefore, the correct option is **both 1 and 2** (bicuspid valve and tricuspid valve).

---