Which answer is correct?

Use `functools.reduce(lambda a, b: b + a, s)`. Functional approach.

— fp_hobbyist

Use `"".join(reversed(s))`. The `reversed()` built-in returns a reverse iterator.

— iterator_fan

Use `s.reverse()`. Strings have a reverse method like lists.

— list_mindset

Use `s[::-1]`. Slice notation with step -1 reverses any sequence.

— slice_master