Explanation:
0.001×4:
[tex]\begin{gathered} 0.001\text{ = }\frac{1}{1000} \\ we\text{ know these by looking at the place value of the last number.} \\ \text{place value is thousandth} \end{gathered}[/tex][tex]\begin{gathered} 4\text{ = }\frac{4}{1} \\ 0.001\times4\text{ = }\frac{1}{1000}\times\frac{4}{1} \\ \text{(option D)} \end{gathered}[/tex]