Solving a physics problem is . . .
 A. . . . meant to happen very quickly, as long as you have memorized the correct equation and answer. 
 B. . . . a basic "plug-and-chug" process, in which you are given some numbers, you "plug" them into an equation, and an answer is given. 
 C. . . . a step-by-step process that takes time, and is essential for learning physics concepts. 
 D. . . . an optional activity, not really required in order to understand the physics concepts.