Robert works at a car dealership. Each month, he receives a base salary of $1,870.00, plus a commission of $378.00 for each vehicle he sells. Which of the following equations could be used to determine Robert's total income each month?

(Let x represent the number of cars sold by Robert and y represent his total monthly income.)
y = $378x + $1,870
y = $378x
$1,870y = $378x
y = $1,870x + $378