The correct answer is: $5/16$
Explanation
To convert a terminating decimal to a fraction, write the decimal over a power of 10 (depending on the number of decimal places) and then simplify.
Steps:
- Write as a fraction over $10^4$ because there are four decimal places:
$$0.3125=\frac{3125}{10000}$$
- Divide numerator and denominator by their greatest common divisor (125):
$$\frac{3125}{10000}=\frac{3125\div125}{10000\div125}=\frac{25}{80}$$
- Reduce further by dividing by 5:
$$\frac{25}{80}=\frac{25\div5}{80\div5}=\frac{5}{16}$$
Therefore, $0.3125=\frac{5}{16}$.