What does the diff notation '4d3' indicate?

• A. It adds a new line after line 3.
• B. It deletes line 4 from the original file.
• C. It changes lines 3-4 in the original file.
• D. It copies line 3 from the original to the new file.

Answer: (B)

Diff patch notation uses concise commands where the operation comes after the line numbers. The letter d stands for delete. So 4d3 means delete line 4 from the original file. After applying the patch, the line that was originally line 5 moves up to become line 4, and the file loses that one line. It’s a straight deletion, not an addition or a modification of content.