Concept:The Tropic of Capricorn receives the Sun’s rays vertically when it is the December solstice.Explanation:The Sun is overhead at the Tropic of Capricorn (23.5∘ S) on December 22nd.On this date, the Southern Hemisphere has its summer solstice, while the Northern Hemisphere has winter solstice.Therefore, the correct option is December 22nd.Answer:D. December 22nd.