The project manager should do first to manage the budget is to meet with the project team to analyze the actual cost to determine deviations. This is the first step in the control cost process, which involves monitoring the status of the project to update the project costs and manage changes to the cost baseline2. By analyzing the actual cost, the project manager can identify the causes and sources of the cost variance, and evaluate the impact and implications on the project performance and objectives. The project manager can also use various tools and techniques, such as earned value analysis, forecasting, and variance analysis, to measure and report the cost performance and status2. Based on the analysis, the project manager can then decide on the appropriate actions and responses to bring the project back on track, such as requesting additional funds, reducing scope, adjusting resources, or implementing corrective or preventive actions2.

Option A is not a good choice, because it is premature and passive. The project manager should not ask the project sponsor for assistance in getting the budget back on track before analyzing the actual cost and determining the deviations. The project manager should first understand the nature and extent of the cost variance, and then present the facts and data to the project sponsor, along with possible solutions and recommendations. The project manager should also demonstrate their own initiative and responsibility in managing the budget, rather than relying on the project sponsor to solve the problem.

Option C is not a good choice, because it is pessimistic and irresponsible. The project manager should not inform the stakeholders that the project will be finished over budget before analyzing the actual cost and determining the deviations. The project manager should first assess the situation and explore the options to improve the cost performance and meet the budget expectations. The project manager should also communicate the cost status and issues to the stakeholders in a timely and transparent manner, and seek their feedback and support, rather than delivering bad news without any justification or action plan.

Option D is not a good choice, because it is hasty and presumptuous. The project manager should not issue a change request including the analysis to increase the budget before analyzing the actual cost and determining the deviations. The project manager should first verify the accuracy and validity of the cost data, and evaluate the feasibility and necessity of increasing the budget. The project manager should also consider the impact of the change request on the project scope, schedule, quality, and stakeholder satisfaction, and obtain the approval of the change control board before implementing the change2.