Correct option is B
• Alt + Tab is used to switch between open applications/windows.
• Holding Alt and pressing Tab cycles through all active programs.
Information Booster:
• Windows + Tab → Task View (all windows)
• Alt + Shift + Tab → reverse navigation
Additional Knowledge:
• Shift + Ctrl (Option A) – no such function
• Alt + Ctrl (Option C) – not used for switching
• Shift + Tab (Option D) – reverse tab movement within apps