Please choose the correct answer to the question: In an experiment, a scientist named Pavlov rang a bell before he fed his dogs, which made the dogs drool. Soon the dogs would drool when they heard the bell, even if they did not receive any food. What type of response did the dogs exhibit?

Answer1: an instinct Answer2: an inherited trait Answer3: a learned behavior Answer4: a conscious behavior

Answer format: answer1/answer2/answer3/answer4
Answer: answer3