A Palindrome Is a Word or Phrase That Reads the Same

A palindrome is a word or phrase that reads the same forward or backward. Consider the methods palindrome and isPal shown below:
Public boolean palindrome(String string)
{
Return isPal(string, 0, string.length() - 1) ;
}
Private boolean isPal(String string, int left, int right)
{
If (left >= right)
{
Return true;
}
Else if (string.charAt(left) == string.charAt(right) )
{
Return isPal(string, left + 1, right - 1) ;
}
Else
{
Return false;
}
}
The method palindrome as shown here would be considered to be a ____ method.

A) recursive
B) terminating
C) helper
D) static