StringBuffer is used to create  ______________.Select one:a.an immutable Stringb.a mutable String

1. Break Down the Problem

The question asks for the purpose of a StringBuffer in programming languages like Java. Specifically, we need to identify whether StringBuffer is used to create an immutable String or a mutable String.

2. Relevant Concepts

• Immutable String: An immutable string cannot be changed after it is created. Every modification results in a new string being created.
• Mutable String: A mutable string can be modified after it is created without creating a new instance.

3. Analysis and Detail

StringBuffer is a class in Java that allows for the creation of strings that can be modified after their creation, which means it can be altered in terms of length and content without the overhead of creating multiple string objects. This is in contrast to the standard String class in Java, which is immutable.

4. Verify and Summarize

Since StringBuffer is designed to allow modification of the string content, it clearly creates a mutable string. Therefore, the correct answer is b. a mutable String.

Final Answer

b. a mutable String