Question

four fourth roots of unity=?

Answer 1

plus minus 1 and plus minus iota

Answer 2

x^4=1

Answer 3

factorize it then

Answer 4

root0 = exp(0*2πi/4) = 1
root1 = exp(1*2πi/4) = i
root2 = exp(2*2πi/4) = -1
root3 = exp(3*2πi/4) = -i

Its easy to check that each of these to the fourth power is 1.
Your answer is 1