A wireless monitored process has fixed cost of $40,000 per year and variable cost of $30 per unit. An IoT-based process using “Internet of Things” technology has fixed costs of $80,000 per year. If the two processes break even at a production level of 4000 units per year, the variable cost of the IoTbased process is closest to:

(a) $10 per unit

(b) $20 per unit

(c) $30 per unit

(d) $40 per unit