Which of the Following Is True Regarding Ozone Depletion in Antarctica

Which of the following is true regarding ozone depletion in Antarctica?

A) Increasing levels of ultraviolet radiation have not actually been measured at this time.
B) The atmosphere above Antarctica has experienced a complete loss of protective ozone.
C) Maximum ozone depletion occurs during the Antarctic spring, following the development of polar stratospheric clouds in winter.
D) There has actually been a decrease in ultraviolet levels measured at the surface-which is contrary to what is predicted by ozone depletion models.