Mercury is highly hazardous and hence its concentration is expressed in the units of ppb (micrograms of Hg present in 1 L of water). Permissible level of Hg in drinking water is 0.0335 ppb. Which of the following is an alternate representation of this concentration?

A

$$3.35 \times 10^{-2}\ \text{mg dm}^{-3}$$

B

$$3.35 \times 10^{-5}\ \text{mg dm}^{-3}$$

C

$$3.35 \times 10^{-5}\ \text{mg m}^{-3}$$

D

$$3.35 \times 10^{-4}\ \text{g L}^{-1}$$