Answer:
i
Explanation:
The powers of i repeat in cycle of 4. For example, here are the first 4:
1: i
2: -1
3: -i
4: 1
If a number is divisible by 4, i to the power of that number would be 1. So, i^20 is 1, but we are multiplying it by i again, so the answer would be 1 * i = i