The practice of disallowing the admission in court of illegally obtained evidence is known as

The practice of disallowing the admission in court of illegally obtained evidence is known as Exclusionary Rule
According to the circumstance, sometimes an evidence of a crime couldn't be used in front of the court
For example:
If evidence is forcefully stolen from the hands of the witness, that evidence wouldn't be able to be used in the case

The answer to your question would be b