Explanation:

Box 1: Yes
Class extension - Method wrapping and Chain of Command.
The functionality for class extension, or class augmentation, has been improved. You can now wrap logic around methods that are defined in the base class that you're augmenting. You can extend the logic of public and protected methods without having to use event handlers. When you wrap a method, you can also access public and protected methods, and variables of the base class. In this way, you can start transactions and easily manage state variables that are associated with your class.
Box 2: Yes
In the following example, the wrapper around doSomething and the required use of the next keyword create a Chain of Command (CoC) for the method. CoC is a design pattern where a request is handled by a series of receivers. The pattern supports loose coupling of the sender and the receivers
[ExtensionOf(classStr(BusinessLogic1))]
final class BusinessLogic1_Extension
{
str doSomething(int arg)
{
// Part 1
var s = next doSomething(arg + 4);
// Part 2
return s;
}
}
Box 3: Yes
Instance and static methods can be wrapped by extension classes. If a static method is the target that will be wrapped, the method in the extension must be qualified by using the static keyword.
Box 4: No
Wrapper methods must always call next.
Note: Wrapper methods in an extension class must always call next, so that the next method in the chain and, finally, the original implementation are always called. This restriction helps guarantee that every method in the chain contributes to the result.
In the current implementation of this restriction, the call to next must be in the first-level statements in the method body.
Here are some important rules:
* Calls to next can't be done conditionally inside an if statement.
* Calls to next can't be done in while, do-while, or for loop statements.
* A next statement can't be preceded by a return statement.
* Because logical expressions are optimized, calls to next can't occur in logical expressions. At runtime, the execution of the complete expression isn't guaranteed.
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/extensibility/method-wrapping-coc

Explanation:

Box 1: Table extension
Isolate all new vendor exclusion codes as a new assembly by creating a table named VendExclusions.
Implement the Excel integration for the Vendor Exclusion List form.
The table extension object allows you to add additional fields or to change some properties on a table provided by the Dynamics 365 Business Central service. In this way, you can add data to the same table and treat it as a single table.
Box 2: Unique key
Create an index for the table named PrimaryIdx that uses the following fields: CustAccount, ItemId, VendAccount.
Box 3: Build and synchronize the database.
A project property lets you specify that the synchronize operation for the database should be performed every time that you build the project. This can be useful when you're making changes to the table structure for an application. Each time that you build, you will know that the database is synchronized with the tables as they are defined in the project.
Reference:
https://docs.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-table-ext-object
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/dev-tools/build-operations#synchronizing-

Explanation:

Box 1: Build the code in the DevOps pipeline.
Box 2: Asset library
Run the export to the Asset library in Microsoft Dynamics Lifecycle Services (LCS).
Box 3: Select Maintain and Apply updates.
eprovision the target environment
If you copy a database between environments, the copied database won't be fully functional until you run the Environment reprovisioning tool to make sure that all Commerce components are up to date.
Follow these steps to run the Environment reprovisioning tool.
* In your project's Asset Library, in the Software deployable packages section, click Import.
* From the list of shared assets, select the Environment Reprovisioning Tool.
* On the Environment details page for your target environment, select Maintain > Apply updates.
* Select the Environment Reprovisioning tool that you uploaded earlier, and then select Apply to apply the package.
* Monitor the progress of the package deployment.
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/database/dbmovement-scenario- exportuat#back-up-to-the-asset-library