Express the Ratio in Lowest Terms $2 \mathrm {~cm} \text { to } 10 \mathrm {~mm}$

Multiple Choice

Express the ratio in lowest terms. $2 \mathrm {~cm} \text { to } 10 \mathrm {~mm}$

A) $\frac { 2 } { 1 }$
B) $\frac { 5 } { 1 }$
C) $\frac { 10 } { 1 }$
D) $\frac { 4 } { 1 }$
E) $\frac { 1 } { 1 }$