An organization wants to run their custom application in the cloud in a flexible and...

The correct answer is B. Platform as a service. Here's why:

Context of the Question: The organization wants to run a custom application in the cloud in a flexible and scalable way without managing any infrastructure.

Google Cloud Product Relevance:

Platform as a Service (PaaS) provides a platform that allows customers to develop, run, and manage applications without dealing with the complexity of building and maintaining the underlying infrastructure.

Google Cloud's App Engine is an example of a PaaS offering. It enables organizations to deploy custom applications in a fully managed environment where scaling, load balancing, and infrastructure management are handled automatically.

Why Not Other Options:

A. Infrastructure as a service: IaaS requires the organization to manage the underlying infrastructure (like virtual machines, networks, and storage), which is not suitable if the organization does not want to manage any infrastructure.

C. Network as a service: NaaS is focused on network connectivity and does not provide the capabilities needed to run custom applications.

D. Software as a service: SaaS provides pre-built applications managed by a provider; it is not suitable for running custom applications.

Google Cloud Digital Leader References:

For more on PaaS, refer to the Google App Engine documentation.