Calculate the Dilution Ratio of a Solution of 100 Microliters $\frac { 1 } { 5 }$

Multiple Choice

Calculate the dilution ratio of a solution of 100 microliters of serum diluted with 900 microliters of saline. Write the ratio in simplest form using a fraction.

A) $\frac { 1 } { 5 }$
B) $\frac { 2 } { 5 }$
C) $\frac { 3 } { 11 }$
D) $\frac { 1 } { 10 }$
E) $\frac { 3 } { 10 }$