Which of the Following Best Describes Why We Have Seasons

Which of the following best describes why we have seasons on Earth?

A) The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
B) Earth's elliptical orbit means we are closer to the Sun and therefore receive more intense sunlight at some times of year than at others.
C) The tilt of Earth's axis causes the northern hemisphere to be closer to the Sun than the southern hemisphere in summer,and visa versa in winter.
D) The varying speed of Earth in its orbit around the Sun gives us summer when we are moving fastest and winter when we are moving slowest.