Given the following data: written premiums $=$$$100,$ loss reserves $=45,$ underwriting expenses incurred $=30,$ unearned premium reserves $=25,$ losses $+$ loss adjustment expenses incurred $=60,$ earned premiums $=90,$ surplus $=50,$ what is the value of the expense ratio?

$\frac{30}{100}=0\mathrm{.}30$

$\frac{30}{90}=0\mathrm{.}33$

$\frac{30}{50}=0\mathrm{.}60$

$\frac{30+60}{100}=0\mathrm{.}90$