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Identify the correct explanation for the Earth's orbit around the sun.
A. Earth has inertia to keep moving in a straight line, but it's own gravity forces it toward the sun.
B. Earth has inertia to keep moving in a straight line, but the sun's gravity keeps pulling Earth toward it.
C. Earth has no inertia; the sun's gravity just keeps pulling on it, but Jupiter is the second largest planet, so it keeps pulling Earth toward it.
D. The sun has inertia and Earth's gravity pulls the sun in orbit around the Earth.