Electrostatics and hydrophobic effects both contribute to stabilizing double stranded nucleic acids; which of the following best accounts for this? select one: a. the hydrogen bonding between bases (electrostatics) and base stacking (hydrophobic) b. phosphate-phosphate repulsion (electrostatics) and exclusion of water from the interior of the duplex (hydrophobic). c. repulsion between exocyclic amines on adenine, cytosine, and guanine and carbonyls on thymine, guanosine, and cytosines (electrostatics) and base stacking (hydrophobic). d. the hydrogen bonding between bases (electrostatics) and the repulsion of water from the backbone (hydrophobic). e. none of the above.