1. "Long Lasting Energy" (LLE) produces a laptop battery unit named "Wolf," at constant marginal cost of $10. Market research has determined that two types of customers buy LLE batteries: "heavy users," who are willing to pay up to $50 for a Wolf unit and "light users," willing to pay up to $30 for a Wolf unit. There are 2000 light users and 1000 heavy users. If LLE only produces Wolf batteries, what price maximizes its profit? (a) $60 (b) $50 (c) $40 (d) $30