Is zero $(0)$ a complex number?

Hint: To answer this question, see the standard form of a complex number. Complex number is written as the mixture of a real number and an imaginary number, it is expressed mathematically as $a + ib$, where $a\;{\text{and}}\;b$ are real numbers and $i$ is the imaginary unit which is equals to $\sqrt { - 1} $.

Complete step by step solution:
 In order to find out if zero is either a complex number or not, we will first see the form of a complex number (that is how a complex number is expressed or general form of complex number).
A complex number is expressed as a mixture of a real number and an imaginary number and also a complex number is represented by that is expressed as follows
$z = a + ib$
Where $a\;{\text{and}}\;b$ are real numbers and $i$ is the imaginary unit which is equal to $\sqrt { - 1} $.
Now coming to the question,
We can express zero as complex number by putting value of $a\;{\text{and}}\;b$ both equal to zero as follows
$0 = 0 + i0 = 0 + 0 = 0$
Therefore we can say that yes, zero is a complex number.
So, the correct answer is “YES”.

Note: Each and every possible number in mathematics is a complex number, because a complex number is the parent branch of all other number groups like there are two branches of complex numbers real numbers and imaginary numbers. And as we know the real number group includes all the numbers used in physical quantities and calculations either rational one or irrational. So in either case zero or any number is a complex number.