MathematicsMedium178×since 2002Q5294Let z = 1 + ai be a complex number, a > 0, such that z³ is a real number. Then the sum 1 + z + z² + . . . . .+ z¹¹ is equal to :A−1250 3 i- 1250\,\sqrt 3 \,i−12503iB1250 3 i1250\,\sqrt 3 \,i12503iC1365 3i1365\,\sqrt 3 i13653iD−-− 1365 3i1365\,\sqrt 3 i13653iCheck answerSkip