Which of the following statements about the molecular arrangement of actin and mysin In myofibre is/are incorrect ?
(i) Each actin (thin filament) is made of 2F (filamentous) actins.
(ii) F-actin is the polymer of G (globular) actin.
(iii) 2F0actins are twisted into a helix.
(iv) Two strands of tropomyosin (protein) lie in the grooves of F-actin.
(v) Troponin molecules (complex proteins) are distributed at regular intervals on the tropomyosin.
(vi) Troponin forms the head of the myosin molecule.
(vii) The myosin is a polymerised protein.

Options

A. (i), (iii) and (vii)
B. (ii), (iv) and (v)
C. Only (vi)
D. Only (iii)

Explanation

To determine which statements about the molecular arrangement of actin and myosin in myofibrils are incorrect, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i)**: "Each actin (thin filament) is made of 2F (filamentous) actins."
- **Analysis**: This statement is correct. The thin filament (actin) is indeed composed of two strands of filamentous actin (F-actin) twisted together.

2. **Statement (ii)**: "F-actin is the polymer of G (globular) actin."
- **Analysis**: This statement is also correct. F-actin (filamentous actin) is formed by the polymerization of G-actin (globular actin) monomers.

3. **Statement (iii)**: "2F-actins are twisted into a helix."
- **Analysis**: This statement is correct. The two strands of F-actin are indeed twisted into a helical structure.

4. **Statement (iv)**: "Two strands of tropomyosin (protein) lie in the grooves of F-actin."
- **Analysis**: This statement is correct. Tropomyosin proteins run along the grooves of the F-actin filament.

5. **Statement (v)**: "Troponin molecules (complex proteins) are distributed at regular intervals on the tropomyosin."
- **Analysis**: This statement is correct. Troponin complexes are indeed spaced at regular intervals along the tropomyosin.

6. **Statement (vi)**: "Troponin forms the head of the myosin molecule."
- **Analysis**: This statement is incorrect. Troponin does not form the head of the myosin molecule; instead, it is a separate complex that interacts with tropomyosin and actin. The myosin head is part of the myosin protein itself.

7. **Statement (vii)**: "The myosin is a polymerized protein."
- **Analysis**: This statement is correct. Myosin is indeed a polymerized protein, consisting of multiple myosin molecules.

### Conclusion:
The only incorrect statement is **(vi)**: "Troponin forms the head of the myosin molecule." Therefore, the answer is that statement (vi) is incorrect.

### Final Answer:
The incorrect statement is (vi).