An Elections Officer Wants to Model Voter Turnout (Y) in a Precinct

An elections officer wants to model voter turnout (y) in a precinct as a function of the type of precinct. Consider the model relating mean voter turnout, E(y), to precinct type: $$\begin{array} { l } E ( y ) = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } \text {, where } x _ { 1 } = 1 \text { if urban, } 0 \text { if not } \\x _ { 2 } = 1 \text { if suburban, } 0 \text { if not } \\\text { (Base level = rural) } \\\end{array}$$
Interpret the value of $\beta _ { 0 }$ .
A) the mean voter turnout for rural precincts
B) the $y$ -intercept of the line
C) the difference between the mean voter turnout for urban and rural precincts
D) the mean voter turnout for urban precincts