Box 1: Public Cloud -

With a public cloud, there is no capital expenditure on server hardware etc. You only pay for cloud resources that you use as you use them.

Box 2: Private Cloud -

A private cloud exists on premises, so you have complete control over security.

Box 3: Hybrid Cloud -

A hybrid cloud is a mix of public cloud resources and on-premises resources. Therefore, you have a choice to use either.

Box 1: No -

You cannot add physical servers to the public cloud. You can only deploy virtual servers in the public cloud. You can extend a private cloud by deploying virtual servers in a public cloud. This would create a hybrid cloud.

Box 2: Yes -

A hybrid cloud is a combination of a private cloud and public cloud. Therefore, to create a hybrid cloud, you must deploy resources to a public cloud.

Box 3: No.

It is not true that a private cloud must be disconnected from the Internet. Private clouds can be and most commonly are connected to the Internet. "Private cloud" means that the physical servers are managed by you. It does not mean that it is disconnected from the Internet.

Reference:

https://azure.microsoft.com/en-gb/overview/what-are-private-public-hybrid-clouds/

Private + Azure Cloud = Hybrid

N-Y-Y is the correct.

Why?

1) Easy (It is a PaaS, NOT a IaaS)

2) Multiple pricing plans are available for Azure App Service and it's really easy to choose an option that can accommodate your business and technical needs.

You can see this on: Basic & Standard Service Plan:

https://azure.microsoft.com/en-us/pricing/details/app-service/windows/

3) A PaaS solution that hosts web apps in Azure does provide the ability to scale the platform automatically. This is known as autoscaling. Behind the scenes, the web apps are hosted on virtual machines running IIS. Autoscaling means adding more load balanced virtual machines to host the web apps.

Think about Scale-Out & Scale-Up (This is the Autoscaling feature of PaaS)

https://docs.microsoft.com/en-us/azure/app-service/manage-scale-up

Option B, NO. Because VM is not a PaaS.

Custom app in first-line tells that it can't be SaaS.

Multiple installations in last line of the question tells that it can't be PaaS.

In PaaS, u don't install stuff, only application files and data are to be given in PaaS.

--> Option left IaaS.

Box 1: No -

Building a data center infrastructure is capital expenditure, not operation expenditure.

Box 2: Yes -

OpEx is ongoing costs (costs of operations) such as staff salaries.

Box 2: Yes -

OpEx is ongoing costs (costs of operations) such as leasing software. If you purchased software as a one-off purchase, that would be CapEx, but leasing software is ongoing so it's OpEx.

First line says "Azure Cosmos DB is a fully managed platform-as-a-service (PaaS)"

https://docs.microsoft.com/en-us/azure/cosmos-db/account-databases-containers-items

Reference:

https://azure.microsoft.com/en-us/overview/what-is-saas/

https://azure.microsoft.com/en-us/overview/what-is-iaas/

https://azure.microsoft.com/en-us/overview/what-is-paas/

-- Nested Resource Groups are not allowed

-- Only One Resource Group is Necessary

-- A Resource Group can contain any Region Resources