Early brain stimulation studies of wanting and liking were conducted by __________.

A) Maslow and McClelland
B) Knutson and colleagues
C) Olds and Milner
D) Duckworth and Seligman

Olds and Milner conducted early brain stimulation studies of wanting and liking in rats, which led to the discovery of the brain's reward system. A and D are incorrect as Maslow and McClelland's work focuses on human motivation and Duckworth and Seligman's work is related to psychological resilience and happiness. B is not the correct answer as Knutson and colleagues did not conduct the earliest brain stimulation studies on wanting and liking.