You create a custom connector for the National Weather Service (NWS). The NWS provides two types of forecasts: by grid points and by coordinates. Here is an example of the grid points URL:
https://api.weather.gov/gridpoints/{office}/{grid X},{grid Y}/forecast, 
where the office is an NWS office responsible for a section of the grid. You need to define the Policy details for the NWS connector. 
Please select the Policy template for the NWS connector.

Answer options:

A.Set HTTP header
B.Set property
C.Set Host URL
D.Set query string parameter
E.Set header/query parameter value from URL

Correct Answer: C 
A custom connector is an API wrapper around the REST API. When you develop your application using REST API services, you need to describe the API`s operations before exporting your APIs. There are three approaches to how to create the API definitions: Using a blank custom connector
Using an Open API definition
Using a Postman Collection
Then you need to secure your Web APIs and set the authentication type for your custom connector. In the end, when you test a new custom connector, you can use it in Power Apps, Power Automate, and Azure Logic Apps. 
If you need to change the connector`s behavior during the run time, like to route a call to a different endpoint, the custom connector`s Policies (Number 1) help you define the URL templates of your dynamic URL. One of the Policy templates is the "Set Host URL" (Number 2). This template replaces the host URL with the URL generated from the "URL Template" expression (Number 3).

The URL template expression for the NWS looks like: 
https://api.weather.gov/gridpoints/@connectionParameters(`nwsoffice`)/@connectionParameters(`gridX`),@connectionParameters(`gridY`)/forecast 
where the nwsoffice, gridX, and gridY are the path parameters. You can define these parameters in the Request section of the Definition stage (Number 1). 

All other options are examples of the Policy templates. They are irrelevant to the current task. 
For more information about custom connector’s Policy templates, please visit the below URLs: 

https://docs.microsoft.com/en-us/connectors/custom-connectors/policy-templates
https://docs.microsoft.com/en-us/connectors/custom-connectors/policy-templates/dynamichosturl/dynamichosturl
https://www.youtube.com/watch?v=PmfrG57-9Hc&t=581s