B. If Kumar sings, then the audiences dance.
C. Unless audience do not dance, the concert will be successful.
F. Kumar sings, only if Vina dances.
G. Vina dances.
H. The concert is successful.
Now if we start with G Vina Dances then as per F Kumar sings then as per B Audience dance then as per C concert will not be succesful but H contradicts this. So option A is wrong.
Moreover as per the statement F, Kumar sings only if Vina dances, this does not implies that whenever Vina dances, kumar sings.
Option B: A, C, F, G and H
A. If Kumar sings, then the audiences sleep.
C. Unless audience do not dance, the concert will be successful.
F. Kumar sings, only if Vina dances.
G. Vina dances.
H. The concert is successful.
Now if we start with G Vina Dance then as per F Kumar sings then as per A Audience sleep and if audience sleep they will not dance then as C concert will be successful which is same as H.
But as per the statement F, Kumar sings only if Vina dances, this does not implies that whenever Vina dances, Kumar sings. Hence even this is not always true.
Option C: E, D, G, B and H.
B. If Kumar sings, then the audiences dance.
D. Only if audience dance, the concert will be successful.
E. If Vina dances, then Kumar sings.
G. Vina dances.
H. The concert is successful.
Now if we start with G Vina dances then as per E Kumar sings then as per B audience dance and if audience dance then as per D concert will be successful and then H says concert is successful. Hence option C is the answer.