Read these lines: "he would now have comprehended that Work consists of whatever a body is obliged to do, and that Play consists of whatever a body is not obliged to do. And this would help him to understand why constructing artificial flowers or performing on a tread-mill is work, while rolling ten-pins or climbing Mont Blanc is only amusement." According to the quoted lines, what separates work from play?

1. The two definitions are given in matching form, and only one word changes between them. 2. Work is whatever a body is obliged to do, and play is whatever a body is not obliged to do. 3. So obligation is the whole of the difference, option A. 4. The examples confirm it, since climbing a mountain is far harder than making paper flowers yet counts as amusement. 5. That same pair of examples rules out option D, which would put the mountain on the side of work. _Source: Mark Twain, The Adventures of Tom Sawyer (1876), public domain_