Many scientists believe that life begins in the ocean long ago. For age man used the ocean to discover and explore new lands. Now man spends a great deal of time or money discover the ocean. We know it is rich at minerals which the world need. We know too that it contains a plenty of food for all the people in the world. We know that if the salt were taken from it, it’s water would turn the deserts into rich farm lands. We know a great deal about this land frontier, as it has called. But we still need to learn many more about it.

PS版显影液是碱性溶液，其组成成分有哪些。（）

A、显影剂、保护剂、溶剂

B、显影剂、润湿剂、溶剂

C、显影剂、保护剂、润湿剂、表面活性剂

D、显影剂、保护剂、润湿剂、溶剂