According to paragraph 4, what was James Watt's major achievement? A. He was able to apply his understanding of physics to invent a variety of scientific instruments and tools for skilled crafts workers. B. He taught university physics courses to outstanding students whose observations led to many patented inventions. C. He improved the efficiency of Newcomen's engine by preventing energy from being lost. D. He redesigned Newcomen's engine so that it no longer needed a separate condenser.