One of ABC Company's competitors has learned that ABC Company has a total expense of $22,500 at the 15,000-unit level of activity and total expense of $29,500 at the 20,000-unit level of activity. Assume that the relevant range includes all of the activity levels mentioned in this problem. Using the high-low method, what would be the competitor's prediction of total expected costs at 18,000 units? $25,200 $26,700 $27,000 O $26,000 $26.400