1. Consider a marginal cost function MC = 5 + Q, where MC indicates the marginal cost in the unit of dollars and Q is the quantity of output. Which of the following statements interprets the marginal cost function correctly?

1. Producing one more unit of output costs $5.
2. Producing the Q-th unit of output costs $(5 + Q) more than producing the (Q - 1)th unit of output.
3. Producing the Q units of output costs $(5 + Q).
4. Producing one unit of output costs $(5 + Q) on average.