Which one of the following is correct pairing of a body part with the kind of muscle tissue present in it ?

Options

A. Biceps of upper arm - Smooth muscle fibres
B. Abdominal wall - Voluntary smooth muscle
C. Iris - Involuntary smooth muscle
D. Heart wall - Involuntary unstriated muscle

Explanation

To determine the correct pairing of a body part with the kind of muscle tissue present in it, we need to analyze the three types of muscle tissues: striated (skeletal), smooth (unstriated), and cardiac muscles.

### Step-by-Step Solution:

1. **Identify the Types of Muscle Tissue:**
- **Striated Muscle (Skeletal Muscle):** These muscles are attached to bones and are responsible for voluntary movements. They have a striped appearance due to the arrangement of fibers.
- **Smooth Muscle (Unstriated Muscle):** These muscles are not under voluntary control and are found in the walls of hollow organs (e.g., stomach, intestines). They do not have a striped appearance.
- **Cardiac Muscle:** This type of muscle is found only in the heart. It is involuntary and has a striated appearance similar to skeletal muscle.

2. **Analyze the Options:**
- **Option 1:** Bicep - This muscle is a skeletal muscle, so it is striated, not smooth.
- **Option 2:** Abdominal wall - The muscles here are also skeletal muscles (striated), not smooth.
- **Option 3:** Iris - The iris contains smooth muscle, which is involuntary and unstriated.
- **Option 4:** Heart muscle - This is cardiac muscle, which is striated but involuntary.

3. **Determine the Correct Pairing:**
- The only correct pairing from the options provided is **Option 3: Iris with Smooth Muscle**. The iris contains smooth muscle, which is involuntary.

### Conclusion:
The correct pairing of a body part with the kind of muscle tissue present in it is **Option 3: Iris - Smooth Muscle**.