Ape Do Good Screen Printing specializes in screen printing t-shirts in San Francisco, California. It sells its most popular template for US$10 and has a marginal cost, including a blank t-shirt and the printing, of US$6. Ape Do Good Screen Printing recently ran a difference-in-differences experiment and determined the demand elasticity is -5. Should Ape Do Good Screen Printing raise or lower price? What is the optimal price?