Explanation
According to the PMBOK Guide 7th Edition, one of the principles of project management is to collaborate with stakeholders. This means that the project manager should engage the team and other stakeholders in the planning, execution, and monitoring of the project, and seek their input and feedback. When a new request to integrate more features to a product arises, the project manager should discuss the problem with the team and decide how to do the work together, as this will help to find the best solution that meets the stakeholder expectations and the project constraints. Asking the team to accelerate the iterations, verifying the team performance, or recommending an increase in the budget are not collaborative strategies, as they do not involve the team in the decision-making process, and they may not address the root cause of the problem or the impact of the new request on the project scope, schedule, quality, and risks. References: PMBOK Guide
7th Edition, page 11-12.