Which recurrence defines the number of ways to choose kkk items from nnn?
(nk)=(n−1k)+(n−1k−1)\binom{n}{k} = \binom{n-1}{k} + \binom{n-1}{k-1}(kn)=(kn−1)+(k−1n−1)
(nk)=(n−1k)+(n−1k)\binom{n}{k} = \binom{n-1}{k} + \binom{n-1}{k}(kn)=(kn−1)+(kn−1)
(nk)=(nk−1)+(n−1k−1)\binom{n}{k} = \binom{n}{k-1} + \binom{n-1}{k-1}(kn)=(k−1n)+(k−1n−1)
(nk)=(n−1k−1)+(n−1k−1)\binom{n}{k} = \binom{n-1}{k-1} + \binom{n-1}{k-1}(kn)=(k−1n−1)+(k−1n−1)