C-10-Q040mediumsingle_mcqn!n!n! এর সংজ্ঞা-an(n−1)(n−2)⋯3⋅2⋅1n(n-1)(n-2)\cdots 3 \cdot 2 \cdot 1n(n−1)(n−2)⋯3⋅2⋅1bn+(n−1)+⋯+1n + (n-1) + \cdots + 1n+(n−1)+⋯+1cnnn^nnndn⋅(n−1)n \cdot (n - 1)n⋅(n−1)