IaaS: (infrastructure as a service) A third-party cloud provider rents infrastructure such as servers, virtual machines, networks, and storage. Users are still responsible for managing and provisioning this hardware and installing applications. CaasS:( containers as a service) In CaaS, cloud users can deploy containers, i.e. software packages that combine applications with the libraries, dependencies, and settings that they need to run predictably and reliably. PaaS: (platform as a service) PaaS is a cloud computing model where a third-party provider delivers hardware and software tools to users over the internet. Usually, these tools are needed for application development. SaaS: (Software-as-a-Service) SaaS is a method of software delivery that allows data to be accessed from any device with an internet connection and a web browser. In this web-based model, software vendors host and maintain the servers, databases, and the code that makes up an application.

SaaS is right. It stands for Software as a Service.

Its A, infrastructure as a service is correct

Software-as-a-Service (SaaS) This cloud computing service offers application software to subscribers on-demand over the Internet. The provider charges for the service on a pay-per-use basis, by subscription, by advertising, or by sharing among multiple users (e.g., web-based office applications like Google Docs or Calendar, Salesforce CRM, and Freshbooks). (P.2811/2795)

Nice graphical explanation https://www.redhat.com/en/topics/cloud-computing/iaas-vs-paas-vs-saas?sc_cid=7013a000002pgROAAY&gclid=Cj0KCQiAtJeNBhCVARIsANJUJ2HZoylx8DNlaB8xUGsChRwZ488iEnoy30Ij-j6MfLG9GQGTqeJVKskaAqovEALw_wcB&gclsrc=aw.ds

correct

CRM tool is considered the software here. I hope these automatically generated answers are correct.