a. Suppose a CD player tries to detect whether its partner is CD player instead of a DD player, by looking for external signals that are at least as typical for DD players than for CD players. Draw a diagram to explain how two boundaries b_L and b_H are optimally determined. Show on the diagram where it is optimal to respond C versus D. Also explain what happens to the boundaries when detection becomes more cautious by raising the minimum likelihood ratio.

B. What is the meaning of the LDD detection strategy?

c. What is the main problem with a detection strategy of looking for "truth-telling" signals from CD players? Explain how the LDD strategy overcomes this problem.