Evaluate the marginal cost of expanding Pfizer's vaccine production facilities.

Cost Components	Fixed Costs ($)	Variable Costs per Unit ($)	Production Volume (units)
Vaccine Production Facilities	4,500,000,000	2	2,000,000,000

Requirements:

Calculate the marginal cost per unit.

Determine the break-even point for the vaccine production facilities expansion.

Analyze how changes in production volume affect the marginal cost.

Provide recommendations for optimizing vaccine production costs.