Question

Have opened up new horizons for proactive and reactive investigations of consumer fraud because an investigator can begin developing a fraud case when unnecessary repairs are recommended.

Answer 1

I've seen the choices of this question which are a. Ponzi schemes b. Advanced fees c. Decoy appliances/vehicles d. Accomplice-witnesses.

The answer is a. decoy.  It happens when the business wants to sell all products even if there are damages. Or they just wanted to use it as a snare or trap to let the consumer make the defective product work when it is actually broken. Sometimes these are just products that already have gone repair and was sent back to be sold out. The business wanted to sell all and get profits. 

Answer 2

I believe the answer is . Decoy appliances/vehicles      
The majority of this fraud is targeted the people who do not really pay attention to the specs of the product they use.
For example, many repairment targets older people by giving them advice to fix parts of their computer that's working fine.