What's the answer to this math problem?

[Lotos]

My calculator is being a ninny, so it gives me some answer other than one on the page.

Expressed in simplest form, i¹⁶ + i⁶ - 2i⁵ + i¹³ is equivalent to:

1
-1
i
-i

Anyone want to help?  I'd greatly appreciate it.

[PsychoYoshi]

i is periodic.

i^1=i
i^2=-1
i^3= -i
i^4= 1

i^5=i
i^6=-1
i^7=-i
etc.