Greg would like to provide a more effective controlling idea for his paper. Which sentence should replace the following to effectively state the controlling idea? (Remember you don't want to change the meaning.)

A. Science and a lot of other things are needed to design a fun and working roller coaster.
B. Designing an exciting roller-coaster ride involves imagination and creativity, but it also requires using science.
C. Quite a bit of knowledge is needed to figure out how the best roller coasters work.
D. Roller coasters have to be fun, so the scientists who design and build them must know something about amusement parks.
E. Hard work, science, and having lots of other skills are needed to design popular roller coasters.