Joshua sells a pack of pens for $3.15, which is 5 percent more than he pays for them. Which equation will help find x, the amount he pays for a pack of pens? How many solutions will this equation have?
A.) x + 0.05x = 3.15, which has infinitely many solutions
B.) x + 0.5x = 3.15, which has one solution
C.) x + 0.05x = 3.15, which has one solution
D.) 0.05x = 3.15, which has no solution