How to convert a string str to lowercase characters?Astr.lower()Bstr.toLower()Cstr.toLowerCase()

Step 1: Break Down the Problem

The question asks for the correct method to convert a string to lowercase characters in programming. We have three options provided:

1. str.lower()
2. str.toLower()
3. str.toLowerCase()

Step 2: Relevant Concepts

When working with strings in programming, it's important to understand the methods available for manipulating strings. Different programming languages have different syntax and method names for converting strings to lowercase.

Step 3: Analysis and Detail

• Option A: str.lower() — This is commonly used in Python to convert a string to lowercase.
• Option B: str.toLower() — This method does not exist in common programming languages like Python or JavaScript.
• Option C: str.toLowerCase() — This is a method used in Java and JavaScript to convert a string to lowercase.

Step 4: Verify and Summarize

Among the options provided:

• str.lower() is valid in Python.
• str.toLower() is not valid in most programming contexts.
• str.toLowerCase() is valid in Java and JavaScript.

Final Answer

The correct methods depend on the programming language. str.lower() is correct for Python, and str.toLowerCase() is correct for Java and JavaScript. Therefore, the answer varies based on the context, but if you need a general answer, the most commonly recognized option is C. str.toLowerCase() for JavaScript and Java.