Consider three hosts A, B, and C using Code Division Multiple Access (CDMA) with chip length m = 4. Their chips are the following:

A: +1 - 1 +1 -1; B: +1 +1 - 1 -1; C: +1 - 1 - 1 + 1

Show the resulting signal S when C transmits a 1 and B transmits a 0.

Discuss and show how we can infer from S that A did not transmit.