Greek prefixes are used to compactly annotate the order of magnitude of a quantity. What is Nano $($n$)$ equivalent to$?$ Note that there may be more than one answer to select. The $\text{'}^\text{'}$ special character is used to denote exponent.

Question $6$ options:

$2^-10$

$10^-9$

$10^-6$

$2^-30$

$2^-20$