A language with string manipulation facilities uses the following operations.head(s) - returns the first character of the stringstail(s) - returns all but the first character of the stringsconcat (s1, s2) - concatenates string s1 with s2.The output of concat (head(s), head(tail(tail(s)))), where s is acbc is

• A. ab
• B. ba
• C. ac
• D. aa