The correct answer is option 'C' - Windows 95.

Explanation:
The Start button and Start menu were introduced in Windows 95, which was released by Microsoft on August 24, 1995. Windows 95 was a major milestone in the history of Microsoft Windows as it brought significant changes and improvements to the operating system's user interface.

Here is a detailed explanation of the introduction of the Start button and Start menu in Windows 95:

1. Windows 1 and Windows 3:
- Windows 1, released in 1985, did not feature a Start button or Start menu. It had a simple graphical user interface (GUI) with tiled windows.
- Windows 3, released in 1990, also did not have a Start button or Start menu. It introduced the concept of overlapping windows and improved multitasking but lacked the iconic Start menu.

2. Introduction of the Start button and Start menu in Windows 95:
- Windows 95 introduced a completely redesigned user interface that included the Start button and Start menu.
- The Start button was located on the taskbar, which is a horizontal bar at the bottom of the screen. It featured the Windows logo and served as the main access point to various functions and programs.
- When the Start button was clicked, it opened the Start menu, a hierarchical menu that provided access to programs, documents, settings, and other system functionalities.
- The Start menu included a list of frequently used programs, a search function, and various options for customization.
- The introduction of the Start button and Start menu in Windows 95 greatly improved the user experience by providing a centralized and easily accessible location for launching applications and accessing system features.

3. Evolution of the Start button and Start menu:
- The Start button and Start menu became iconic features of Microsoft Windows and were retained in subsequent versions.
- Windows 7, released in 2009, introduced some visual changes to the Start menu, such as larger icons and the ability to pin programs to the taskbar.
- In Windows 8, released in 2012, Microsoft replaced the traditional Start button and Start menu with a new full-screen Start screen that featured live tiles. However, due to user feedback, the Start button was reintroduced in Windows 8.1, with a modified Start menu.
- Windows 10, released in 2015, further refined the Start menu by combining elements from Windows 7 and Windows 8, allowing users to switch between a traditional Start menu and a full-screen Start screen.

In conclusion, the Start button and Start menu were introduced in Windows 95, revolutionizing the user interface of Microsoft Windows and providing users with a more convenient way to access programs and system functionalities.