ACT Practice Question: Complex Numbers and Summation

 
Here is a practice question on parabolas in the coordinate plane.

What does $i – i^2 + i^3 – i^4 + \cdots + i^{97} – i^{98}$ equal, where the imaginary number $i$ is defined as $i^2=-1$ ?

1. $\quad -i-1$
2. $\quad -i+1$
3. $\quad 0$
4. $\quad i-1$
5. $\quad i+1$