Good morning, I did not understand the following question:
A kVp meter reads 86 kVp, and the turns ratio of the high-voltage step-up transformer is 1200. What is the true voltage across the meter?

 

I note the strange way the diodes connected to the x-ray tube are wired...

The kVp meter is probably calibrated/labeled to reflect the output of the HV transformer so
86000/1200 -> 71 volts

 

I note the strange way the diodes connected to the x-ray tube are wired...

That's a misprint.