• Statement (A) is Correct: Molecular conformation refers to the spatial arrangement of atoms or functional groups in a molecule that can be interconverted purely by rotation about single bonds.
• Statement (B) is Correct: Conformational changes occur without the cleavage or formation of covalent bonds.
• Statement (C) is Correct: Ethane ($CH_3-CH_3$) possesses an infinite number of interconvertible torsional conformations between fully eclipsed and fully staggered extremes.
• Why (D) and (E) are Incorrect: Conformers of ethane interconvert millions of times per second across a minimal rotational energy barrier (~$12\text{ kJ/mol}$), making individual isolation impossible. The staggered conformer has minimum torsional strain and is the most stable, while the eclipsed conformer is the least stable.
• Conclusion: (A), (B), and (C) only are correct.

• Statement (I) is True: Ribosomal translation in all living organisms incorporates exclusively L-stereoisomers of $\alpha$-amino acids into polypeptide chains.
• Statement (II) is False: The "L" descriptor designates absolute configuration relative to L-glyceraldehyde, not the direction of optical rotation. While all protein amino acids are L-configured, some rotate plane-polarized light to the right (dextrorotatory, $+$, e.g., L-alanine, L-isoleucine, L-glutamate) and others to the left (levorotatory, $-$) in neutral aqueous solutions.
• Conclusion: Statement (I) is true but Statement (II) is false.

Correct option: (3) Statement (I) is true but Statement (II) is false.