Determine the set of all complex numbers zzz such that z+zˉ=4z + \bar{z} = 4z+zˉ=4.
A circle with radius 2 centered at the origin.
A vertical line x=2x = 2x=2.
A horizontal line y=2y = 2y=2.
The single point 2+0i2+0i2+0i.