A research student is investigating the factors that stabilise the folded structure of a protein. They note that residues Phe-26 and Ile-75 contribute to a well-defined hydrophobic cluster in the core of the protein. To determine the contribution of these residues’ hydrophobic side chains to protein stability, they make mutants F26A and I75A. They then determine the stability of the wild type (WT) protein and each mutant.

What is the expected order of stability (from most stable to least stable), assuming that the main contribution of these residues to stability is through their side chain hydrophobic interactions?