Magento 2's architecture uses code to bootstrap a custom module that resides in app/code.
What two files are required to make a module usable? (Choose two.)

How do you set the custom block MyCompany\MyModule\Block\A as a child for the block named product.info using layout XML?

A merchant tasks you to keep sales managers out of the system configuration backend pages.
How do you do that using the admin interface?

Assume that a customer's cart only includes one downloadable product.
What effect will it cause on the quote object?

Your module, MyCompany_MyModule, is using the frontName mymodule. You need to locate the class responsible for the frontend path /mymodule/custom.
What file contains the controller class for the frontend path /mymodule/custom?