Degree 3, zeros: 1,-3-i, find the remaining zeros

Since its to the 3rd degree, then there are 3 zeros, meaning that there's only one remaining zero. And since "-i" is listed among the current zeros, then the remaining zero must include the opposite: + i so therefore the remaining zero is - 3+i. Also its the most likely answer per the information given.

Answer: - 3+i