In the query 
"extend ProcessEntropy = -log2(PCoHValue/TPCoHValue)*(PCoHValue/TPCoHValue)" 
PCoHValue means the ProcessCountOnHost value.

Answer options:

A.True
B.False

Correct Answer: A 
Entropy calculation used to help identify Hosts where they have a high variety of processes (a high entropy process list on a given Host over time). This helps us identify rare processes on a given Host. Rare here means a process shows up on the Host relatively few times in the last 7days. 
Reference: 

https://github.com/Azure/Azure-Sentinel/blob/master/Hunting%20Queries/SecurityEvent/ProcessEntropy.yaml