Which of the following are Nonreal Complex numbers?

As the last question you asked about this, take out anything that isn't what you are looking for.

You are wanting the list of complex numbers so take out anything that's real (rational and irrational numbers).

So anything that has a square root of a negative number of an "i" term will be complex.

-21/7 + i
√(-4)
√(-21)

That one that has a zero in the denominator is still undefined so won't be real or complex.