17. 如圖(二)所示電路,若 i(t) = 20 cos (200t - 45˚),求之值為何?(A) 20 cos (200t-45˚) V(B) 20 cos (200t + 45˚) V(C) 40 cos (200t-45˚) V(D) 40 cos (200t + 45˚) V