Final answer:
Aristotle is the philosopher who believed the Earth must be spherical because the sun and moon are, and he had various observations to support this theory.The correct answer is b. Aristotle.
Step-by-step explanation:
The individual who believed that if the sun and moon are spherical, then the Earth must be spherical as well, is Aristotle. Aristotle proposed multiple arguments for the Earth's roundness. One was the circular shadow the Earth cast on the Moon during a lunar eclipse. Another observation by Aristotle was that certain stars visible in Egypt are not visible further north, suggesting a curved surface. This information, along with other evidence, contributed to his conclusion that the Earth is spherical.
Aristotle believed that if the sun and moon are spherical, so is the earth. He argued that the Earth is spherical because it casts a circular shadow on the Moon during a lunar eclipse. In addition, some stars visible from Egypt are not seen further north, which further supported his belief in a spherical Earth.