For which value of x is parallelogram upper x upper y upper z upper a a rectangle? quadrilateral upper x upper y upper z upper a is shown with diagonals upper x upper z and upper a upper y intersecting in the middle of the figure. the part of the diagonal between upper a and the intersection of the diagonals is labeled 5 x minus 5. the part of the diagonal between upper z and the intersection is labeled 3 x plus 3. a. 2 b. 3 c. 4 d. 5