One of the ways to do this is by facilitating the Scrum events, such as the Sprint Review, where the Scrum Team and the stakeholders inspect the product Increment and adapt the Product Backlog. In this situation, where there is a conflict among the stakeholders about the budget and the funding, your two best options are:
Encourage the stakeholders to focus on delivering the highest value items for the next Sprint.
This option aligns with the purpose of the Sprint Review, which is to collaborate on what was done in the Sprint and what to do next. By encouraging the stakeholders to focus on delivering value, you are helping them prioritize the most important features or functionalities that can maximize the return on investment and reduce risk. This can also help them align their expectations and goals, and create a shared understanding of the product vision.
Ask for a short break for people to calm down and be objective. This option aligns with your role as a facilitator, who helps the participants have constructive and respectful conversations. By asking for a short break, you are giving them a chance to cool off and regain their composure.
This can also help them be more objective and rational, and avoid emotional reactions that can escalate the conflict or damage the relationship.

A Product Owner or Scrum Master can be dedicated to one team OR participate as a member on more than one team. How much time they spend with each team will directly impact effectiveness of the team.

As a Scrum Master, you are accountable for establishing an environment where the Scrum Team can be effective and deliver valuable products. One of the ways to do this is by supporting the Product Owner in managing the Product Backlog and engaging with the stakeholders. In this situation, where there is a performance issue with the product, your best option is:
Encourage the Product Owner to bring the performance concerns to the rest of the Scrum Team and work together to improve the Definition of Done. This option aligns with the principle of empiricism, which is the foundation of Scrum. Empiricism means that you make decisions based on what is known, rather than what is assumed or predicted. By encouraging the Product Owner to bring the performance concerns to the rest of the Scrum Team, you are helping them inspect the product Increment and adapt the Product Backlog based on transparent feedback from the stakeholder. You are also helping them collaborate on improving the Definition of Done, which is a shared understanding of what it means for a product Increment to be complete and potentially releasable. The Definition of Done should reflect the quality standards and expectations of the stakeholders, and should be updated as needed to ensure that the product meets their needs and delivers value.

Explanation
B: The Scrum Master coaches the Scrum Team and the organization how to work empirically. This is a true statement, as the Scrum Master is responsible for helping everyone understand and apply the principles and practices of Scrum, which is based on empirical process control. The Scrum Master can teach the Scrum Team and the organization how to use transparency, inspection, and adaptation to deliver valuable products in a complex environment.
C: The Scrum Master facilitates Scrum events as requested or needed. This is a true statement, as the Scrum Master is responsible for ensuring that all Scrum events take place and are positive, productive, and kept within the timebox. The Scrum Master can facilitate the communication and collaboration among the Scrum Team and the stakeholders during the Sprint Planning, Daily Scrum, Sprint Review, and Sprint Retrospective.
References:
Scrum Guide 2020, page 6: "The Scrum Master is accountable for establishing Scrum as defined in the Scrum Guide. They do this by helping everyone understand Scrum theory and practice, both within the Scrum Team and the organization." Scrum Guide 2020, page 13: "The purpose of each event in Scrum is to create an opportunity for inspection and adaptation. These events are specifically designed to enable critical transparency and inspection." Professional Scrum Master II Course, page 13: "The Scrum Master serves the Scrum Team by facilitating the Scrum events and ensuring that they are effective and valuable."

Explanation
The Sprint Review is an event that inspects the outcome of the Sprint and determines future adaptations. The Product Owner has the authority to release the Increment to production at any time, but this does not mean that the Sprint has to be stopped or changed. The stakeholders can provide feedback and suggestions for the product, but they cannot interfere with the Sprint Goal or the Sprint Backlog within the Sprint. The Scrum Team can decide to:
Continue sprinting but shorten the Sprint length to allow for shorter feedback loops (A), which is a valid option if the Scrum Team agrees that this will improve their agility and value delivery. However, this should not be done frequently or arbitrarily, as it may disrupt the rhythm and focus of the team.
Continue sprinting and include the customer feedback in the Product Backlog, which is the most appropriate option as it respects the empirical nature of Scrum and allows the Product Owner to prioritize and order the Product Backlog based on new insights and stakeholder needs.
References: : [Scrum Guide], The Sprint Review : [Scrum Guide], The Product Owner : [Scrum Guide], The Sprint : [Scrum Guide], The Product Backlog