The correct answer is: A. IDE
An IDE, or Integrated Development Environment, is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of a source code editor, build automation tools, and a debugger.
In VB, the IDE is called integrated because we can access virtually all of the development tools from within the IDE. This includes the source code editor, the compiler, the debugger, and the project manager. This makes it easy to develop and debug VB programs.
The other options are incorrect because they are not development tools. A toolbar is a bar that contains buttons that can be used to perform common tasks. A menu bar is a bar that contains menus that can be used to access different commands.