To get expanded form of 0.1250, 5 should be multiplied with ____

The correct option is C $\frac{1}{1000}$
Place value of decimal digits after decimal point towards right is $\frac{1}{10}$, $\frac{1}{100}$, $\frac{1}{1000}$, $\frac{1}{10000}$...

To get the expanded form of decimal, each digit has to be multiplied with its place value.

Here, 5 has to be multiplied with $\frac{5}{1000}$.