To determine the correct pairing of compensators with their typical dB magnitude versus frequency characteristics, let's first understand the characteristics of lead and lag compensators:

• Lead Compensator: A lead compensator enhances the high-frequency gain and provides a positive phase angle. Its Bode magnitude plot typically starts flat, increases to a peak, and then flattens at a higher magnitude level.
• Lag Compensator: A lag compensator decreases the high-frequency gain and provides a negative phase angle. Its Bode magnitude plot generally starts flat, declines to a lower level, and then flattens at a lower level.

Now, let's analyze the images:

1. Image (i): This plot starts at 0 dB, decreases, and then flattens. This behavior matches the typical characteristic of a lag compensator.
2. Image (ii): This plot starts at 0 dB, increases, and then flattens at a higher level. This behavior matches the typical characteristic of a lead compensator.
3. Image (iii): This appears to be another representation of a lag compensator. It starts at 0 dB, decreases more prominently, and flattens at a lower level.

Based on the analysis, the pairings are as follows:

• (ii) is a lead compensator.
• (iii) is a lag compensator.

Thus, the correct answer is:

(b) and (c)