5. The sound level at a distance of $2.0\mathrm{m}$ from a source is $120\mathrm{dB}$. At what distance is the sound level $100\mathrm{dB}$?
(A) $40\mathrm{m}$
(B) $30\mathrm{m}$
(C) $20\mathrm{m}$
(D) $10\mathrm{m}$
(E) $5\mathrm{m}$.

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