Answer:
Maybe did you mean dm(decimetre)? If you did, then the answer is:
B. 2m
If you didn't...Well the most close aproximation to that is Da(Dalton) which is a unit of mass, so the options would have not any sense
Explanation:
Keep this in mind:
[tex]1dm=0.1m[/tex]
and just do the convertions you may need:
[tex]20dm*\frac{0.1m}{1dm} =2m[/tex]
