MathematicsEasy64×since 2002Q2999∑k=020(20Ck)2\sum\limits_{k = 0}^{20} {{{\left( {{}^{20}{C_k}} \right)}^2}}k=0∑20(20Ck)2 is equal to :A40C21{}^{40}{C_{21}}40C21B40C19{}^{40}{C_{19}}40C19C40C20{}^{40}{C_{20}}40C20D41C20{}^{41}{C_{20}}41C20Check answerSkip