If the elasticity of demand for college textbooks is -0.1, and the price of textbooks increases by 20\%, how much will the quantity demanded change, and in what direction? 
选项为:A:The quantity demanded increases by 2\%  B:The quantity demanded decreases by 20\%  C:The quantity demanded decreases by 2\%  D:The quantity demanded remains the same  请回答其中一个选项.