@ thor,
Take options one by one.
A) HSIG --> As per condition 2 and 3, geeta and saira should come consecutive. (False)
B) SGHI --> Take age of Saira as x then G becomes x-1 (since their age diff is 1)
H becomes x-4 (since max age diff could be 3)
I becomes x-7 (since max age diff could be 3)
Now to follow condition no one age(H) + age(G) > age(I) + age(S) => x-4+x-1 > x-7+x => 2x-5 > 2x-7 (True)
C) IGSH --> Take age of Irfan as x then G becomes x-3 (since max age diff could be 3)
S becomes x-4 (since their age diff is 1)
H becomes x-7 (since max age diff could be 3)
Now to follow condition no one age(H) + age(G) > age(I) + age(S) => x-7+x-3 > x+x-4 => 2x-10 > 2x-4 (False)
D) IHSG --> Take age of Irfan as x then H becomes x-3 (since max age diff could be 3)
S becomes x-6 (since max age diff could be 3)
G becomes x-7 (since their age diff is 1)
Now to follow condition no one age(H) + age(G) > age(I) + age(S) => x-3+x-7 > x+x-6 => 2x-10 > 2x-6 (False)
So option B is correct.
Hope it is helpful.