• Non-Covalent Forces Stabilizing Biomolecules: The stable native conformations of proteins, nucleic acids, and biological membranes are maintained by a cooperation of multiple non-covalent interactions:
• Hydrogen Bonds: Stabilize secondary structures ($\alpha$-helices, $\beta$-sheets) and DNA double helix base pairing.
• Electrostatic Interactions (Salt Bridges): Formed between oppositely charged ionizable amino acid side chains (e.g., $\text{Lys}^+/\text{Arg}^+$ with $\text{Asp}^-/\text{Glu}^-$).
• Hydrophobic Interactions: The major driving thermodynamic force packing non-polar hydrophobic side chains into macromolecular interiors, maximizing water entropy.
• Van der Waals Forces: Weak transient dipole attractions between closely packed atoms in the hydrophobic core.
• Conclusion: All four forces (A), (B), (C), and (D) contribute to biomolecular stabilization.

Correct option: (3) (A), (B), (C) and (D).