Correct Answer & Explanation
Option A
• The sentence describes a universal truth or a general scientific fact.
• Universal truths are always expressed in the Present Indefinite Tense (Simple Present).
• The structure for Present Indefinite Tense is Subject + V1 (s/es for 3rd Person Singular) + Object.
• 'The earth' is a 3rd person singular subject, so the verb 'move' takes 's' and becomes 'moves'.