Assume you are selling a product in which at a price of $10, you can sell 90 units. When the price increases to $11, you can only sell 63 units. Given this change in price and sales, answer the following:________. 
A. What is the price elasticity of demand for your product? 
B. Is demand elastic, unit-elastic or inelastic? 
C. What is the change in revenue for this product from the price increase?