A company manufactures acoustic guitars. The table shows the number of units that the company sold each month over a nine-month period beginning in January.
Month, x 1 2 3 4 5 6 7 8 9
Units, y 150 300 380 425 425 480 520 550 575
Which equation best models the situation?
a y=148.4 x-1-154
b y=46.4x+191.7
c y=148.4 x-1+154
d y= -46.4x+191.7