Counting & ProbabilityChallengeBinomial Theorem, Pascal & Combinatorial Identities ShareBinomial Theorem, Pascal & Combinatorial Identities · Challenge problemEvaluate ∑k=0n(nk)(2nn−k)\displaystyle\sum_{k=0}^{n}\binom{n}{k}\binom{2n}{n-k}k=0∑n(kn)(n−k2n) in closed form.A(3nn)\binom{3n}{n}(n3n)B(4nn)\binom{4n}{n}(n4n)C−(3nn)-\binom{3n}{n}−(n3n)D(6nn)\binom{6n}{n}(n6n)Check Show answer Walk through it step by step Practice more like this Review this concept