You want to append a new line "Log entry" to an existing file "log.txt" without overwriting it. Which C# code snippet correctly does this?

hard🚀 Application Q8 of Q15

C Sharp (C#) - File IO

AFile.AppendAllText("log.txt", "Log entry\n");

BFile.WriteAllText("log.txt", "Log entry");

Cnew StreamWriter("log.txt").WriteLine("Log entry");

DFile.ReadAllText("log.txt").WriteLine("Log entry");

Step-by-Step Solution

Solution:

Step 1: Understand append vs overwrite
File.AppendAllText adds text to the end without erasing existing content.
Step 2: Validate options
File.AppendAllText("log.txt", "Log entry\n"); uses AppendAllText correctly; others overwrite or misuse methods.
Final Answer:
File.AppendAllText("log.txt", "Log entry\n"); -> Option A
Quick Check:
Appending text = File.AppendAllText [OK]

Quick Trick: Use File.AppendAllText to add without overwriting [OK]

Common Mistakes:

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