Last month 10,000 units of a product were manufactured, and the total cost per unit was $60. At this level of production, the variable cost is $30 per unit, and the fixed cost is $30 per unit. If 10,500 units are manufactured the next month, and the costs remain within the same relevant range

1. total variable cost will increase
2. fixed costs will increase in total
3. variable cost per unit will increase
4. total cost per unit will remain unchanged