Explanation:

- Option 1: Zero

Fixed costs remain constant regardless of production levels, so they are not zero when production is zero. They include rent, salaries, and other overheads.

- Option 2: Negative

Fixed costs cannot be negative. They are expenses that must be paid, like rent or salaries, even if no goods are produced.

- Option 3: Positive

Fixed costs are positive as they are incurred regardless of production levels. Examples include lease agreements and insurance.

- Option 4: Equal to variable cost

Variable costs change with production levels. Fixed costs do not, so they are not equal to variable costs when production is zero.