Consider the Sequence of SG Devices Shown in Figure Q7 $\langle+z \mid+x\rangle\langle+x \mid+\theta\rangle+\langle+z \mid-x\rangle\langle-x \mid-\theta\rangle$

Consider the sequence of SG devices shown in figure Q7.7. Which of the expressions below gives the proper quantum amplitude that an electron emerging from the first SG device leaves via the - channel of the final device? (Do not assume that the inner product is commutative.)

Figure 07.7

A) $\langle+z \mid+x\rangle\langle+x \mid+\theta\rangle+\langle+z \mid-x\rangle\langle-x \mid-\theta\rangle$
B) $|\langle+z \mid+x\rangle\langle+x \mid-\theta\rangle|^{2}+|\langle+z \mid-x\rangle\langle-x \mid-\theta\rangle|^{2}$
C) $|\langle-\theta \mid+x\rangle\langle+x \mid+z\rangle+\langle-\theta \mid-x\rangle\langle-x \mid+z\rangle|^{2}$
D) $\langle-\theta \mid+x\rangle\langle+x \mid+z\rangle+\langle-\theta \mid-x\rangle\langle-x \mid+z\rangle$
E) None of the above