If a memory writing speed is $10$K Bytes per nanoseconds $($ns$),$ it will take $\_\_\_\_\_\_\_\_\_\_$ milliseconds to write $20$M Bytes.

Question $3$ options:

$0\mathrm{.}2$

$0\mathrm{.}0002$

$0\mathrm{.}002$

$0\mathrm{.}00002$

$0\mathrm{.}02$