Awarding certificates of appreciation to encourage the team is an action that the project manager can take to motivate the team's performance, because it shows that the project manager recognizes and values the team's efforts and achievements. Certificates of appreciation are a form of positive reinforcement, which is a technique that uses rewards or recognition to increase the likelihood of a desired behavior. Positive reinforcement can motivate and inspire the team to continue working hard and delivering quality results, as well as to increase their satisfaction and loyalty. The other options are not actions that the project manager can take to motivate the team's performance, because they may not address the team's needs or expectations, or they may have negative consequences. Sending a formal notice to team members instructing them to maintain performance may not be effective, because it may imply a lack of trust, respect, or autonomy for the team.
Hiring a few temporary team members to help with the additional work may not be beneficial, because it may create confusion, conflict, or resentment among the team members, as well as increase the complexity and risk of the project. Informing the team about the delivery pressure from the project sponsor may not be helpful, because it may increase the stress and anxiety of the team, and it may not provide any guidance or support for the team to cope with the pressure. References: Positive Reinforcement | PMI - Project Management Institute, The Mindful Project Manager's Guide To Team Motivation: 11 ... - Planio