In such type of questions, clues are given regarding comparisons among a set of persons or things with respect to one or more qualities. The candidate is required to analyse the whole information, form a proper ascending / descending sequence and then answer the given questions accordingly.
(i) There is a group of five girls.
(ii) Kamini is second in height but younger than Rupa.
(iii) Pooja is taller than Monika but younger in age.
(iv) Rupa and Monika are of the same age but Rupa is tallest between them.
(v) Neelam is taller than Pooja and elder Rupa.
To answer the question "who is the youngest person in the group", which of the given statements is superfluous ?
We first find the sequence of height :
By (iii), we have : M < P.
By (v), we have : P < N.
Now, Rupa is tallest and Kamini is is second in height.
So, the sequence of heights is : M < P < N < K < R.
Now, we determine the age sequence :
By (ii), we have : K < R.
By (iii), we have : P < M.
By (iv), we have : R = M.
By (v), we have : R < N.
So, the sequence of ages is : N < R = M < K < P or N < R = M < P < K.
Clearly, only statement (i) is not necessary.
Hence, the answer is (a).