Jonathan is purchasing apples from the grocery store. the apples cost $1.29 $1.29 per pound and there is a $0.25 $0.25 charge to purchase a bag. assuming jonathan needs to buy a bag, which function, c(a), where a is the weight of the apples in pounds, represents the cost of his purchase? c(a)=0.25+1.29 c(a)=1.54a c(a)=1.29a+0.25 c(a)=0.25a