Final answer:
None of the pairs listed (a-d) can interact through an ionic bond at neutral pH. An example of amino acids that can form such an interaction would be aspartic acid and lysine, which form a salt bridge at neutral pH.
Step-by-step explanation:
Examples of two amino acid side chains that can interact with each other through an ionic bond at neutral pH are those of acidic and basic amino acids due to their charges. Specifically, none of the pairs listed in the options (a) Asparagine and Glutamine, (b) Arginine and Lysine, (c) Serine and Threonine, (d) Tyrosine and Tryptophan, are correct, as they cannot form ionic interactions at neutral pH.
An example would be the side chain of aspartic acid (an acidic amino acid with a negative charge) interacting with the side chain of lysine (a basic amino acid with a positive charge). This interaction occurs when the carboxylate group of aspartic acid loses a proton and becomes negatively charged, and the amino group of lysine gains a proton and becomes positively charged, forming a salt bridge.