When a business's expenses change based on factors that occur within the business, these are called___factors.

A. Minimum
B. Retention
C. Internal
D. External

C. Internal

To determine the answer, we need to understand the meaning of each given option.

A. Minimum: This term typically refers to the lowest or smallest amount. It does not specifically relate to expenses changing based on factors within a business.

B. Retention: The concept of retention generally refers to the act of keeping something or someone. It does not directly relate to expenses changing based on internal factors.

C. Internal: This option refers to factors that occur within a business. Internal factors include things like changes in production levels, employee salaries, marketing strategies, and operational costs.

D. External: This option refers to factors that occur outside of a business. External factors may include changes in the economy, market demand, government regulations, or natural disasters.

Based on the description provided, the correct answer is C. Internal factors. These are the factors that cause expenses to change within a business. They are directly related to the operations and decisions made within the organization.