You may have chosen this answer because i is imaginary, but here more than just i makes up the imaginary part of this number. A complex number is a number in the form $\displaystyle{a}+{b}{i}\usepackage{cmbright}\Huge\$ where a and b are real numbers. The term $\displaystyle{b}{i}\usepackage{cmbright}\Huge\$ is referred to as the imaginary part. The correct answer is $\displaystyle{i}\sqrt{{{3}}}\usepackage{cmbright}\Huge\$ .