Consider the Question and two Statements given below: Question: Is Z brother of X? Statement- 1: X is a brother of Y and Y is a brother of Z. Statement- 2: X, Y and Z are siblings. Which one of the following is correct in respect of the Question and the Statements?

The question asks "Is Z brother of X?". To answer this, we need to know if Z is male and if Z is a sibling of X.

Statement-1: "X is a brother of Y and Y is a brother of Z." From "X is a brother of Y", we know X is male. From "Y is a brother of Z", we know Y is male. This establishes that X, Y, and Z are siblings. However, this statement does not specify the gender of Z. Z could be a brother (male) or a sister (female) to Y and X. If Z is male, the answer to the question is 'Yes'. If Z is female, the answer to the question is 'No'. Since Z's gender is not determined, Statement-1 alone is not sufficient.

Statement-2: "X, Y and Z are siblings." This statement tells us X, Y, and Z are siblings. However, it does not specify the gender of any of them, particularly Z. Z could be male or female. For Z to be a brother of X, Z must be male. Since Z's gender is not determined, Statement-2 alone is not sufficient.

Combining Statement-1 and Statement-2: Statement-1 already implies that X, Y, and Z are siblings (with X and Y being male). Statement-2 simply confirms they are siblings. Even with both statements, we still do not know the gender of Z. Z could be a brother or a sister. Therefore, we cannot definitively answer "Is Z brother of X?" with a 'Yes' or 'No'.

Thus, both Statement-1 and Statement-2 are not sufficient to answer the question.