Answer:
The equivalent ratio to the given ratio is;
[tex]4\colon7[/tex]Explanation:
Given the ratio;
[tex]12\colon21[/tex]We want to select an equivalent ratio from the given options.
Let's divide the ratio all through by 3;
[tex]\begin{gathered} \frac{12}{3}\colon\frac{21}{3} \\ 4\colon7 \end{gathered}[/tex]Therefore, the equivalent ratio to the given ratio is;
[tex]4\colon7[/tex]