The agile project leader should explain the new team velocity to the customer and negotiate the scope and schedule of the project accordingly. Team velocity is a measure of the amount of work a team can handle during a single iteration1. It is affected by factors such as team size, skills, experience, and availability2. Since the team has lost two members, the team velocity will likely decrease, which means the team will not be able to deliver the same amount of work as before. The agile project leader should communicate this change to the customer and collaborate with them to prioritize the most valuable features and adjust the release plan3.
Updating the restriction log with the new team capacity (A) is not a sufficient action since it does not address the impact on the project scope and schedule. Explaining the new project requirements to the team (B) is also not a good option since it may overload the team and compromise the quality and value of the product.
Updating the project budget with the released team members is not relevant since the budget has already been reduced by the customer. References:
* 1: Agile Practice Guide, Glossary, page 91
* 2: Agile Practice Guide, Chapter 2, Section 2.4.2.2
* 3: Agile Practice Guide, Chapter 2, Section 2.4.2.3