An example of a complex number is imaginary numbers. Complex numbers are in the form \( a + bi \), where \( a \) and \( b \) are real numbers and \( i \) is the imaginary unit, defined as \( i = \sqrt{-1} \). Imaginary numbers have a real part of 0 and a non-zero imaginary part (e.g., \( 0 + 3i \)).
So, the correct choice among the options provided is imaginary numbers.