If $C=A_{5 \times 3}B$ be such that $\text{rank} \left( A\right)=3$, then Cx=0 and Bx=0 are equivalent systems.

Question

Prove or disprove- If $C=A_{5 \times 3}B$ be such that $\text{rank} \left( A\right)=3$, then $Cx=0$ and $Bx=0$ are equivalent systems.

I do not know wether to prove or disprove it. If it is incorrect then can anyone give a counter example.

If it is true then please give a hint.