The average cost of a long-distance call in the USA in 1985 was 41 cents per minute, and the average cost of a long-distance call in the USA in 2005 was 7 cents per minute. Find the approximate percent decrease in the cost per minute of a long- distance call. (2007 AMC 8, Question \#6) 
选项为:A:$$7$$  B:$$17$$  C:$$34$$  D:$$41$$  E:$$80$$  请回答其中一个选项.