Question: How were thick layers of halite and gypsum deposited beneath the Mediterranean Sea? Choose one: A. At times of high global sea level, the Mediterranean Sea was cut off from the Atlantic Ocean, and the trapped seawater evaporated. B. Large rivers from the surrounding continents increased their flow into the Mediterranean Sea, bringing in more mineral-rich sediments. C. Widespread layers of gypsum and halite were deposited in the deep ocean over millions of years. D. At times of low global sea level, the Mediterranean Sea was cut off from the Atlantic Ocean, and the trapped seawater evaporated.