The correct answer is: A. Winword.exe
Winword.exe is the main executable file for Microsoft Word. It is responsible for loading the Word application and initializing its components. When you double-click on a Word document, or click on the “Start” button and select “All Programs” > “Microsoft Office” > “Microsoft Word,” Winword.exe is the file that is executed.
Word.exe is a shortcut to Winword.exe. When you click on Word.exe, it launches Winword.exe.
Msword.exe is a shortcut to Winword.exe that was used in earlier versions of Microsoft Word. It is no longer used in current versions of Word.
Word2003.exe is the main executable file for Microsoft Word 2003. It is no longer used in current versions of Word.
Therefore, the correct answer is: A. Winword.exe