Eratosthenes, an Ancient Greek Astronomer, Is Famous For

Eratosthenes, an ancient Greek astronomer, is famous for:

A) measuring the diameter of Earth by comparing the direction to the Sun at noon at two different points on Earth.
B) measuring the diameter of Earth by timing how long it took the Moon to traverse Earth's shadow during a lunar eclipse.
C) measuring the relative distances to the Sun and the Moon by timing the exact moments when the Moon was at first and third quarter.
D) measuring the distance to each of the known planets by timing how long it took the planet to orbit the Sun.