Four costs incurred by Chula Vista Farms are summarized below: Cost 1 Cost 2 Cost 3 Cost 4 2.000 units 4.000 units $30,000 $30,000 $21,000 $42,000 $16,000 $26,000 $12,000 $20,000 Which of these costs are strictly variable (as opposed to fixed or mixed costs)? O costs 2 and 3 O cost 2 only O costs 1 and 2 id 2 h O costs 1 and 4