Consider the following including the Question and the Statements : There are 5 members A, B, C, D, E in a family. Question : What is the relation of E to B ? Statement-1 : A and B are a married couple. Statement-2 : D is the father of C. Statement-3 : E is D's son. Statement-4 : A and C are sisters. Which one of the following is correct in respect of the above Question and Statements ?

(a) Statement-1, Statement-2 and Statement-3 are sufficient to answer the Question.
(b) Statement-1, Statement-3 and Statement-4 are sufficient to answer the Question.
(c) All four statements together are sufficient to answer the Question. ✓ UPSC's answer
(d) All four statements are not sufficient to answer the Question.

Why the answer is (c)

• Statement-4 makes A and C sisters, so A is female and A and C have the same father.

• Statement-2 says D is the father of C, so D is the father of A.

• Statement-3 says E is D's son, so E is A's brother.

• Statement-1 says A and B are a married couple, so B is A's husband and E is B's brother-in-law; therefore all four statements are sufficient, which is option (c).

Why the other options are wrong

(a) Statement-1, Statement-2 and Statement-3 are sufficient to answer the Question.: Statements-1, Statement-2 and Statement-3 do not establish any link between A or B and D, so E's relation to B is not determined.
(b) Statement-1, Statement-3 and Statement-4 are sufficient to answer the Question.: Statements-1, Statement-3 and Statement-4 do not establish D as the father of A, so E's relation to B is not determined.
(d) All four statements are not sufficient to answer the Question.: All four statements establish E as A's brother and B as A's husband, so they are sufficient to answer the question.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2023, held on 28 May 2023. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.