Looots of points

shannon went to an auto repair shop and paid $339.50, which included parts that cost $112 and 3.5 hours of labor. joni went to an auto repair shop and paid $455, which included parts that cost $310 and 2.5 hours of labor. which correctly compares the cost of the labor?

shannon paid $7 more per hour for labor.
shannon paid $7 less per hour for labor.
joni paid $85 more per hour for labor.
joni paid $85 less per hour for labor.