Please choose the correct answer to the question: Scientists compared Pluto with other objects in the solar system and found that Pluto is smaller than Earth's moon. This finding caused scientists to question whether Pluto is a planet because

Answer1: Pluto gets less sunlight than Earth's moon Answer2: the other planets are much larger than Pluto Answer3: the other planets have moons and Pluto does not Answer4: Pluto rotates on its axis and the other planets do not

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