HOTSPOT
You have an Azure Web App that uses the URL contoso.azurewebsites.net. The virtual IP address of the web
app is subject to change.
Users must be able to navigate to a custom domain name to access the Web App. You set up the DNS records
for a custom domain at a third party registrar.
You need to configure the web app to use the custom domain name.
For each mapping, which DNS record type should you create? To answer, select the appropriate DNS record
type from each list in the answer area.
Hot Area:
Answer: 
Explanation:
https://azure.microsoft.com/en-gb/documentation/articles/web-sites-custom-domain-name/
I believe the answer is CNAME for both. The Question states the IP address will change, so setting an A record for the root wont work very long.
I think A/CNAME – It states that the virtual IP address of the web
app (contoso.azurewebsites.net) is subject to change.
The web app is a sub-domain.
https://docs.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain
Root is an A record