If zzz is a complex number such that ∣z−3∣=∣z−3i∣|z - 3| = |z - 3i|∣z−3∣=∣z−3i∣, what is the geometric locus of zzz?
The line y=xy = xy=x
The line y=−xy = -xy=−x
The circle x2+y2=9x^2 + y^2 = 9x2+y2=9
The line y=−x+3y = -x + 3y=−x+3