Correct Answer - Option 4 : -2

__Concept:__

The imaginary unit i is defined as i = √-1.

i4n + 1 = i, i4n + 2 = -1, i4n + 3 = -i, i4n = 1, etc.

__Calculation:__

Let z = i-22 + i22

= i-20 i-2 + i22i^{2}

= (i4)-5 × (1/i^{2}) + (i4)^{5} i^{2}

= -1 - 1 (∵ i4n = 1)

= -2