Final answer:
The complex number is -4 + 7i (option b).
Step-by-step explanation:
A complex number is a number that contains both a real part and an imaginary part. The imaginary part is represented by the letter 'i' and is equal to the square root of -1. Therefore, a complex number can be written as a + bi, where 'a' is the real part and 'b' is the imaginary part.
Out of the options given, the complex number is -4 + 7i (option b) because it has both a real part (-4) and an imaginary part (7i).