A one-dollar coin should have a mass of 7.0\:g. Each individual coin may be lighter or heavier by as much as 2.14\%. Joshua has a number of these coins and determines that they have a total mass of 1\:kg. What is the difference between the greatest possible number and the least possible number of these coins that he could have?
Answer Choices
A. 4
B. 5
C. 6
D. 7
E. 8