Final answer:
PaaS (Platform as a Service) is the optimal solution for a web developer creating a web app because it provides a pre-configured platform with built-in software components that facilitate application development without managing underlying infrastructure.
Step-by-step explanation:
The best cloud service type for a web developer intending to create a web app is c. PaaS (Platform as a Service). PaaS provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app. It offers a development environment to application developers that includes a pre-configured feature set. Developers can build applications on the platform using the software components that are built into the PaaS, which can considerably accelerate development time, as compared to needing to build, configure, and provision their own virtual machines and back-end architectures present in IaaS (Infrastructure as a Service).
In contrast, SaaS (Software as a Service) simply provides access to a vendor's cloud-based software and is not a development environment. And MaaS (Monitoring as a Service) is focused on cloud monitoring mechanisms, which would not offer the platform support a developer would need to build a web app.