GMAT Official Guide 2019 How many basic units of currency

Question : 250 basic units of X that is equivalent to 250 basic units of currency Y.
Statement 1: 100 basic units of currency X are equivalent to 625 basic units of currency Y.
Therefore, if 100 units of x = 625 units of y
x units of x = 250 units of y
$$x\ =\ \frac{100}{625}\ \cdot\ 250\ =\ 40$$
Statement 1 is sufficient

Statement 2: 2000 basic units of x are equivalent to 12,500 basic units of currency y.
Therefore, if 2000 units of x = 12,500 unit of y
x unit of x = 250 units of y
$$x\ =\ \frac{2000}{12500}\ \cdot\ 250\ =\ 40$$
Statement 2 is also sufficient.
Final answer is Option D, because each statement alone is sufficient.