8. Bud uses the high-low method of estimating costs. Bud had total costs of $50,000 at its lowest level of activity, when 5,000 units were sold. When, at its highest level of activity, sales equaled 12,000 units, total costs were $78,000. Bud would estimate variable cost per unit as a) $10.00 b) $6.50 0) $4.00 d) $7.53