Teacher:In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Teacher: Now, understand the problem? Solve this instance: Problem: if a 10 percent deposit that has been paid toward the purchase of a certain product is $ 80 , how much more remains to be paid ? 
Options: a ) $ 640 , b ) $ 680 , c ) $ 720 , d ) $ 760 , e ) $ 800
Student:
c