s = 'madam'All of the following expressions produce the same result except one. Which one?S[::-1][::-5]S[::5]S[::-5]None

The expression that produces a different result is S[::5].

Here's why:

1. S[::-1] reverses the string 'madam' to 'madam'.
2. S[::-1][::-5] also gives 'madam' because it first reverses the string and then takes every 5th character from the reversed string. Since 'madam' has less than 5 characters, it returns the whole string.
3. S[::5] takes every 5th character from the original string 'madam'. Since 'madam' has less than 5 characters, it returns the first character 'm'.
4. S[::-5] reverses the string and then takes every 5th character from the reversed string. Since 'madam' has less than 5 characters, it returns the first character from the reversed string, which is 'm'.

So, S[::5] is the expression that produces a different result.