Choose the Most Reasonable Unit of Measure $\left( \mathrm { mm } ^ { 2 } , \mathrm {~cm} ^ { 2 } , \mathrm {~m} ^ { 2 } , \mathrm {~km} ^ { 2 } \right)$

Multiple Choice

Choose the most reasonable unit of measure.
-Area of a cross-section of a drinking glass: 21....... $\left( \mathrm { mm } ^ { 2 } , \mathrm {~cm} ^ { 2 } , \mathrm {~m} ^ { 2 } , \mathrm {~km} ^ { 2 } \right)$

A) $\mathrm { cm } ^ { 2 }$
B) $\mathrm { m } ^ { 2 }$
C) $\mathrm { km } ^ { 2 }$
D) $\mathrm { mm } ^ { 2 }$