Find out the correct match regarding the structure of muscle fibre
`{:("Band","Colour","Filaments"):}`

Options

A. `{:("A - band","Dark","Contains only actin"):}`
B. `{:("I-band","Light","Contains only actin"):}`
C. `{:("A-band","Light","Contains actin and myosin both"):}`
D. `{:("I-band","Light","Contains myosin only"):}`

Answer

To find the correct match regarding the structure of muscle fibers, we need to analyze the options given for the bands, their colors, and the filaments they contain.

### Step-by-Step Solution:

1. **Understand Muscle Fiber Structure**: Muscle fibers consist of myofilaments, which are primarily made up of two types of proteins: actin and myosin. Actin forms thin filaments, while myosin forms thick filaments.

2. **Identify the Bands**:
- **I-band**: This is the light band in skeletal muscles, which contains only actin filaments. It appears light in color and is isotropic.
- **A-band**: This is the dark band that contains both actin and myosin filaments. It appears dark in color and is anisotropic.

3. **Evaluate the Options**:
- **Option A**: A band, color dark, contains only actin.
- **Analysis**: Incorrect, as the A band contains myosin, not just actin.
- **Option B**: I band, color light, contains only actin.
- **Analysis**: Correct, as the I band is indeed light and contains only actin.
- **Option C**: A band, color light, contains actin and myosin both.
- **Analysis**: Incorrect, as the A band is dark, not light.
- **Option D**: I band, color light, contains myosin only.
- **Analysis**: Incorrect, as the I band contains only actin, not myosin.

4. **Conclusion**: The correct match is **Option B**: I band, color is light, and it contains only actin.

### Final Answer:
**Option B: I band, color is light, contains only actin.**

---