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.