The numerator and denominator of a fraction are in the ratio of 2 to 5. If the numerator and denominator are both decreased by 2, the fraction is now equal to . If n = the numerator and d = the denominator, which of the following systems of equations could be used to solve the problem?

2 n = 5 d and 2 n - 4 = d - 2
2 n = 5 d and n - 2 = 2 d - 4
5 n = 2 d and n - 2 = 2 d - 4
5 n = 2 d and 2 n - 4 = d - 2