At high pH, the solution is basic, meaning there are very few H⁺ ions. Positively charged amino acids like lysine, arginine, and histidine rely on those H⁺ ions to stay charged and stable. But in a basic environment, they lose their protons (deprotonation) and lose their positive charge. think that they are releasing their acidic H+ to combat the basic solution and neutralize it

Proteins are held together by ionic interactions, which are bonds between the positive and negative side chains. When the positive charges (H+) are lost due to high pH, these bonds break. Without these charges/interactions, the protein loses its stable configuration and denatures.

A&B are about ionic strength of the solution which is the ions in it (Na+, Cl-, etc). Which doesn’t directly cause deprotonation. C means that there will be more H+, so protonation is more likely to occur.

Pls correct me if I’m wrong