Fill in the code to complete the following method for checking whether a string is a palindrome.

def isPalindrome$($s$)$:

$$ if $($len$($s$)<=1)$: #Base case

$$ return True

$$ elif $\_\_\_\_\_\_\_\_\_$:

$$ return False;

$$ else:

$$ return isPalindrome$($s$[1$:len$($s$)-1])$

$1.($s$[0]!=$ s$[$len$($s$)-1])//$ Base case

$2.($s$[1]!=$ s$[$len$($s$)])//$ Base case

$3.($s$[1]!=$ s$([$len$($s$)-1)]//$ Base case

$4.($s$[0]!=$ s$[$len$($s$)])//$ Base case