23. Let z 1 and z 2 be nth roots of unity which subtend a right angle at the origin. Then n must be of the form: (A) $4 \mathrm { k } + 1$ (B) $4 \mathrm { k } + 2$ (C) $4 \mathrm { k } + 3$ (D) 4 k
23. Let z 1 and z 2 be nth roots of unity which subtend a right angle at the origin. Then n must be of the form:\\
(A) $4 \mathrm { k } + 1$\\
(B) $4 \mathrm { k } + 2$\\
(C) $4 \mathrm { k } + 3$\\
(D) 4 k\\