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:

Given information:

• J is the sister of K
• K is the sister of L
• L is the sister of M
• M is the brother of N

From these statements, we can deduce:

• J, K, and L are all female (since they are referred to as "sister")
• M is male (since M is referred to as "brother")

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Checking statement (A): K and L are sisters.

K is the sister of L is directly stated in the given information.

Statement (A) is necessarily true.

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Checking statement (B): M and N are brothers.

M is the brother of N tells us that M is male, but provides no information about N's gender.

N could be male (making them brothers) or N could be female (making them brother and sister).

Statement (B) is NOT necessarily true.

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Checking statement (C): L is sister of N.

L is the sister of M (given), so L is female.

M is the brother of N (given), which means M and N are siblings.

Since L, M, and N are all siblings in the same family, and L is female, L is the sister of N.

Statement (C) is necessarily true.

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Checking statement (D): J, K, L are females and M is male.

From the given statements:

• J is sister → J is female
• K is sister → K is female
• L is sister → L is female
• M is brother → M is male

Statement (D) is necessarily true.

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Only statement (B) is not necessarily true.

Therefore, the correct answer is Option 2: (B) only.