Which of the Following Accurately Describes ¹⁸O/¹⁶O Ratios of the Oceans

Which of the following accurately describes ¹⁸O/¹⁶O ratios of the oceans?

A) The ¹⁸O/¹⁶O ratio in the ocean is low during the winter because temperatures are too low for ¹⁶O to evaporate.
B) The ratio of oceanic ¹⁸O/¹⁶O in the late summer is high,because the most of the ¹⁶O has evaporated by then.
C) During the winter,¹⁶O is high in the ocean; during warmer periods the isotope ratio is lower.
D) Because ¹⁸O evaporates more readily than ¹⁶O,the oceans have a higher relative abundance of ¹⁶O during the summer.