In a skeletal muscle cell, which of the following is the basic unit of contraction?
(a) Myofibril
(b) Muscle fibre
(c) Sarcomere
(d) Myosin filament

Options

A. Myofibril
B. Muscle fibre
C. Sarcomere
D. Myosin filament

Explanation

To solve the question regarding the basic unit of contraction in a skeletal muscle cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Components of Skeletal Muscle**:
- Skeletal muscle is composed of muscle fibers, which are made up of myofibrils. Myofibrils contain the contractile proteins actin and myosin.

2. **Identifying the Options**:
- (a) Myofibril: These are long, thread-like structures that contain the sarcomeres.
- (b) Muscle fibre: This is a single muscle cell that contains many myofibrils.
- (c) Sarcomere: This is the basic unit of contraction in skeletal muscle.
- (d) Myosin filament: This is one of the proteins involved in muscle contraction but is not the basic unit itself.

3. **Defining the Basic Unit of Contraction**:
- The sarcomere is defined as the smallest functional unit of muscle contraction. It is the segment between two Z-lines and contains the actin and myosin filaments that slide past each other during contraction.

4. **Conclusion**:
- Based on the definitions and roles of each component, the basic unit of contraction in a skeletal muscle cell is the **sarcomere**.

5. **Final Answer**:
- The correct answer is (c) Sarcomere.