Find the odd number / letters / word from the given alternative.

The answer is C. Lamprey.

A rhea is a large flightless bird native to South America. A trout is a freshwater fish of the salmon family. A salmon is a large anadromous fish of the salmon family. A lamprey is a parasitic jawless fish with a sucker-like mouth.

Lampreys are the odd one out because they are the only parasitic fish in the