If J is the sister of K. K is the sister of L. L is the sister of M. M is the brother of N. Then which of the following statements is not necessary true?

(A) K and L are sisters.
(B) M and N are brothers.
(C) L is sister of N.
(D) J, K, L are females and M is male.

Choose the correct answer from the options given below:

(B) only

The correct answer is Option (2) → (B) only

Given:

• J is the sister of K → J is female.
• K is the sister of L → K is female.
• L is the sister of M → L is female.
• M is the brother of N → M is male.

From this, we know:

• J, K, L are all females (because they are sisters).
• M is male.
• N is a sibling of M.

Now check each statement:

(A) K and L are sisters. True – directly given: “K is the sister of L” (so they are sisters).

(B) M and N are brothers. Not necessarily true. M is the brother of N → M is male. But N could be male (then M and N are brothers) or female (then M and N are brother and sister). The statement “M and N are brothers” assumes N is male, which is not given. So this is not necessarily true.

(C) L is sister of N. True – L is sister of M, and M is sibling of N → L and N are siblings, and L is female → L is sister of N.

(D) J, K, L are females and M is male. True – J, K, L are explicitly called sisters (so female), M is called brother (so male).

Conclusion:

Only (B) is not necessarily true (because N’s gender is not specified).

Correct option: (B) only