Step 1: Context: Alfred’s relief suggests the professor’s reaction was positive.
Step 2: Options: Gainsaid (denied), Denigrated (criticized), Ignored (overlooked),
Corroborated (confirmed), Derided (mocked).
Step 3: Corroborated fits as it means the professor confirmed Alfred’s guess.
Step 4: Others imply negative or neutral reactions, clashing with relief.