Consider yourself as a Project Manager and share best suited model in below scenarios $-$

$1$: You are leading a project to develop a mission$-$critical software system for a government agency. The requirements are well$-$defined, and there is little to no room for changes once the project begins. Which project management model would you choose and why?

$2$: You are tasked with developing a prototype for a new product in a highly competitive market. The requirements are not fully known, and there is a need for rapid iterations and frequent feedback from stakeholders. Which project management model would you choose and why?

$3$: Your team is tasked with developing a new mobile application for a startup company. The project requirements are likely to evolve over time, and there is a need for flexibility and adaptability in the development process. Which project management model would you choose and why?

$4$: Your team is working on a project that involves complex and high$-$risk requirements, such as developing a new medical device. There is a need for rigorous risk management and regular validation of design assumptions. Which project management model would you choose and why?

$5$: Your team is responsible for maintaining and updating an existing software system used by multiple departments within your organization. The requirements are stable, and there is a need for continuous improvement and incremental updates to the system. Which project management model would you choose and why?