Question 4 5 points Save Answer Cardinal uses the high-low method of estimating costs. Cardinal had total costs of $25,000 at its lowest level of activity, when 5,000 units were sold. When, at its highest level of activity, sales equaled 10,000 units, total costs were $39,000. Cardinal would estimate variable cost per unitas: A. $7.00 OB. $4.55 oc $2.80 0