What function is used to read a file line by line in Python?

• A. The `read()` method
• B. The `readline()` method
• C. The `get_line()` method
• D. The `file_line()` method

Answer: (B)

The readline() method is specifically designed for reading a file one line at a time. When called on a file object, it reads the next line from the file and returns it as a string, allowing you to control the flow of reading through the file sequentially. This is particularly useful when working with large files, as it enables you to process one line at a time rather than loading the entire file into memory at once.

In contrast, the read() method reads the entire file content at once, which is not as efficient for line-by-line processing. The other options, such as get_line() and file_line(), are not standard methods in Python for file operations, underscoring why they wouldn't be the correct choice for reading lines from a file. Thus, readline() is the appropriate and effective method for the task of reading a file line by line in Python.