Which of the Following Is True Regarding Whether Shirley's Arrangement

Which of the following is true regarding whether Shirley's arrangement that if a store carries her line of scuba gear,it must carry her line of wet suits is legal?

A) It is legal.
B) It is legal unless the items at issue may not be used together.
C) It is per se illegal.
D) If the tying arrangement leads to competitive harm, the court will likely find the arrangement to be illegal.
E) The agreement is legal only if use of the wetsuit enhanced the performance of the scuba gear which is unlikely.