(d) When sales increase by 5%, which of the following should also increase by 5% in a merchandising company? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer. Any boxes left with a question mark will be automatically graded as incorrect.) Variable cost 2 Fixed cost 2 Gross margin 2 Contribution margin Net operating income (e) When sales increase by 5%, which of the following should increase by more than 5% in a merchandising company? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer. Any boxes left with a question mark will be automatically graded as incorrect.) 2 Variable cost Fixed cost Gross margin Contribution margin