Read the following statements and choose the correct option:
A. The extensor muscles of human back reamin in sustained contraction to maintain erect posture against gravity.
B. The extensor mucles are rich red muscle fibres with abundant mitochondria and myoglobin.
1. Statement A is correct but B incorrect.
2. Statement B correct but A incorrect.
3. Statement A is correct and B are correct but B is not hte correct explanation of A.
4. Both the statements A and B are correct but B is not the correct explanation of A.