What is the output of the expression 'hello'.split()?

The expression 'hello'.split() takes the string 'hello' and splits it into a list of substrings based on whitespace characters by default. In this case, since there are no spaces within the string 'hello', the entire string is treated as a single chunk. Therefore, the output is a list containing the string itself: ['hello']. This behavior of the split method is key to understanding how it operates when no specified delimiter is present.

In contrast, other options do not accurately represent the behavior of the split method. The output does not include individual characters as in option C, nor does it contain an empty string as in option D. Additionally, option A incorrectly suggests that the result is simply the same string without any transformation into a list. The correct interpretation shows that the split method is specifically designed to separate strings into lists, which is why ['hello'] is the accurate output.