DIRECTIONS: Read the following passages and answer the questions that follow: PASSAGE ? 4 Scientists have developed a new technique that could be applied worldwide to create an early warning system for massive tsunamis triggered by earthquakes. Scientists from Stanford University have identified key acoustic characteristics of the 2011 Japan earthquake that indicated it would cause a large tsunami. The same technique could be used to create an early warning system for tsunamis, they believe. What is the meaning of the phrase "early warning systems" as used in the passage?

• A. a system giving a problem   
• B. a process of great use
• C. a condition indicating an impending problem
• D. None of these