Determine the Most Appropriate Metric Unit to Go in the Blank

Multiple Choice

Determine the most appropriate metric unit to go in the blank. Choose from $\mathrm{km}, \mathrm{m}, \mathrm{cm}, \mathrm{mm}, \mathrm{L}, \mathrm{ml}, \mathrm{kg}$ , g, and $\mathrm{mg}$ .
-The length of the nail is 29

A) $\mathrm{cm}$
B) $\mathrm{mg}$
C) $\mathrm{ml}$
D) $\mathrm{mm}$