[单选题]
Substance A has a densies rw8 )slf.j4x/qx0w ty of s zk( mmdgkjccpya,rq;-94r6)mzi,+$3.0 \; g/cm^{3}$ and substance B has a density of $4.0 \; g/cm^{3}$. In order to obtain equal masses of these two substances, the ratio of the volume of A to the volume of B will be equal to
