Triangles ABC and DEF are similar as shown in the figure.The area of $\Delta ABC$ is $16$ sq.cm and that of $\Delta DEF$ is $25$ sq.cm.If $BC=2.3$ cm then $EF$ is _______

Question

$\begin{array}{1 1}4\;cm(approx)\\2.4\;cm(approx)\\2.9\;cm(approx)\\3.9\;cm(approx)\end{array} $