The points $z_{1} , z_{2} , z_{3} , z_{4}$ in the complex plane are the vertices of a parallelogram taken in order if and only if

Question

$$\begin{array}{1 1}(1)z_{1}+z_{4}=z_{2}+z_{3}&(2)z_{1}+z_{3}=z_{2}+z_{4}\\(3)z_{1}+z_{2}=z_{3}+z_{4}&(4)z_{1}-z_{2}=z_{3}-z_{4}\end{array}$$