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(B) Let $n_A, n_B, n_C$ be the number of questions selected from sections $A, B, C$ respectively. We have $n_A + n_B + n_C = 15$ with $n_A \ge 4, n_B

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(B) Let $n_A, n_B, n_C$ be the number of questions selected from sections $A, B, C$ respectively. We have $n_A + n_B + n_C = 15$ with $n_A \ge 4, n_B \ge 4, n_C \ge 4$ and $n_A \le 8, n_B \le 6, n_C \le 6$.Possible combinations $(n_A, n_B, n_C)$ are:$1$. $(7, 4, 4): \binom{8}{7} \binom{6}{4} \binom{6}{4} = 8 	imes 15 	imes 15 = 1800$$2$. $(6, 5, 4): \binom{8}{6} \binom{6}{5} \binom{6}{4} = 28 	imes 6 	imes 15 = 2520$$3$. $(6, 4, 5): \binom{8}{6} \binom{6}{4} \binom{6}{5} = 28 	imes 15 	imes 6 = 2520$$4$. $(5, 6, 4): \binom{8}{5} \binom{6}{6} \binom{6}{4} = 56 	imes 1 	imes 15 = 840$$5$. $(5, 4, 6): \binom{8}{5} \binom{6}{4} \binom{6}{6} = 56 	imes 15 	imes 1 = 840$$6$. $(5, 5, 5): \binom{8}{5} \binom{6}{5} \binom{6}{5} = 56 	imes 6 	imes 6 = 2016$$7$. $(4, 6, 5): \binom{8}{4} \binom{6}{6} \binom{6}{5} = 70 	imes 1 	imes 6 = 420$$8$. $(4, 5, 6): \binom{8}{4} \binom{6}{5} \binom{6}{6} = 70 	imes 6 	imes 1 = 420$Total ways $= 1800 + 2520 + 2520 + 840 + 840 + 2016 + 420 + 420 = 11376$.

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