In expressing sound intensity, we take ${10}^{-12}{\mathrm{Wm}}^{-2}$, as the reference level. For ordinary conversation, the intensity level is about ${10}^{-6}{\mathrm{Wm}}^{-2}$. Expressed in decibel, this is

• A

  ${10}^6$

• B

  6

• C

  60

• D

  ${\log }_{\mathrm{e}}\left({10}^6\right)$