If a firm's total costs are $80 when 10 units of output are produced and $90 when 11 units of output are produced, the marginal cost of the 11th unit is

A) $1.
B) $5.
C) $8.09.
D) $10.

Marginal Cost

The cost associated with producing an extra unit of output, crucial for decision-making in production and pricing strategies.

Total Costs

The complete amount of costs incurred by a business to produce a specific amount of goods or services, including fixed and variable costs.