To change a fraction to an equivalent fraction, you can only multiply the numerator and the denominator by the same number (or, multiply the fraction by another fraction equal to 1).
Here you can multiply 2/5 by 2/2 (2/2=1) to get an equivalent fraction.
[tex]\frac{2}{5} \times \frac{2}{2}=\frac{4}{10}[/tex]
The answer is D.