This text describes a problem scientists are trying to solve. This text can be best described as

The correct answer is D) an informational text.

An informational text is intended to convey factual information about a specific topic, often presenting problems, solutions, and scientific findings. Since the text describes a problem scientists are trying to solve, it aligns with the characteristics of an informational text focused on providing knowledge and understanding. If you have any more questions, feel free to ask!