The equation below shows a general equation for a reaction, and the amounts of the substance are written underneath.

AB + CD → AC + BD
(15 g) (?) (?) (10 g)

The total mass of the products is 50g. Which best completes the other two amounts?

A: The amount of CD is 40 g, and the amount of AC is 35 g.
B: The amount of CD is 35 g, and the amount of AC is 40 g.
C: The amount of CD and AC would be the same.
D: The amount of CD and AC is undetermined.