You create an Azure Function that estimates monthly car loan payments. It takes three parameters: total loan amount, loan term (in months), and interest rate. You want to use this estimator in the Power Apps and Power Automate. 
What should you do?

Answer options:

A.Create a Dataverse plug-in
B.Create a Custom connector
C.Create a Dataverse Web API
D.Create a PCF component

Correct Answer: B 
Power Platform provides 300+ connectors. If you need to communicate with services that Microsoft doesn`t have on its list of connectors, you can create your custom connector. A custom connector is an API wrapper around your REST API. You can create such a wrapper for Azure Functions, Azure Web Apps, Azure API apps. 
When you create your application using one of these services, before you can export your application`s APIs, you need to describe the API`s operations by creating API definitions. 
Power Apps or Power Automate portals provide a wizard-type interface for creating a custom connector (Number 1). You need to input the connector name, select the security, and set the authentication type for your custom connector. There are four types of API authentication you can choose from (Number 2). Then you provide the API definition. After the custom connector`s successful test, you push the "Create connector" button (Number 3). And you can use your new custom connector in Power Apps, Power Automate, and Azure Logic Apps. 

Options A, C, and D are incorrect because you don`t need to create a Dataverse plug-in, Web API, or PCF component to connect to the external application. You need to create a custom connector.
For more information about Custom connectors, please visit the below URLs: 

https://docs.microsoft.com/en-us/learn/modules/introduction-power-platform/3-data-connectors
https://docs.microsoft.com/en-us/connectors/custom-connectors/
https://docs.microsoft.com/en-us/connectors/custom-connectors/create-web-api-connector