Whch stuction represents a proportional relationshp?
 A) The cost of purchasing dog food for $1.20 per pound and
 having to pay $6 n shipping
 B) The cost of purchasing gift cards at $20 per card and
 having to pay a $2 och nation fee per card
 C) The cost of purchasing oranges of So yo per orange and
 having a $1 off your total purchase coupon
 D) None of the above represent a proportional relationshp