Solution

The correct answer is adba

EXPLANATION:

A palindromic subsequence is one that remains the same when reversed. The given string is "ababcdabba".

• From this string:
  • "abcba" is a palindromic subsequence ('a', 'b', 'c', 'b', 'a').
  • "abba" is a palindromic subsequence ('a', 'b', 'b', 'a').
  • "abbbba" is not a palindromic subsequence. There are only two 'b's in the input string, and 'abbbba' would require at least four.
  • "adba" is not a palindromic subsequence. There is no 'd' in the input string.

Therefore, the non-palindromic subsequences are 3) abbbba and 4) adba.

Mistake Points Above question two correct answer and ugc also give both are correct answer.