单选题
[阅读理解]Decibels（分贝） measured in water are different from those measured on land. A noise of one hundred-twenty decibels on land causes pain to human ears. In water， a decibel level of one-hundred ninety-five would have the same effect.
Which of the following is discussed in the paragraph？
A.The same noise level produces a different effect on land and in the ocean.
B.Different places may have different types of noises.
C.The decibel is not a suitable unit for measuring underwater noise.
D.Different ocean animals may have different reactions to noises.
正确答案：A
答案解析：本段第一句话就直接给出了答案。