The value of 0.000441 is = ?

Answer: Option C

$$\begin{array}{rl}& =\sqrt{0.000441}\\ & =\sqrt{\frac{441}{{10}^6}}\\ & =\frac{\sqrt{441}}{\sqrt{{10}^6}}\\ & =\frac{21}{{10}^3}\\ & =\frac{21}{1000}\\ & =0.021\end{array}$$