Answer:
Imaginary/Complex. While the i means negative, it can also mean an imaginary integer. Often times, i is described as the square root of negative one, or simply an undefinable/negative integer. Since 80i can be considered both complex and imaginary, imaginary is more fitting due to the fact that i cannot be defined fully by mathematical means other than it meaning "imaginary" or "complex". In conclusion, you should pick both imaginary and complex.
Hope this helps!