O'Neill, Incorporated's income statement for the most recent month is given below. If sales in Store B increase by $30,000 as a result of a $7,000 expenditure in fixed expenses: Select one: a. the contribution margin should increase by $18,000 b. the segment margin should increase by $12,000 c. the contribution margin should increase by $11,000 d. the segment margin should increase by $5,000