Regarding Adaptive Application Control, Azure Defender needs at least _____ weeks of data to define the unique recommendations per group of machines.

Answer options:

A.4
B.3
C.2
D.5

Correct Answer: C
Option A, B, D are incorrect. Option C is correct. Security Center needs at least two weeks of data to define the unique recommendations per group of machines. Machines that have recently been created, or which belong to subscriptions that were only recently enabled with Azure Defender, will appear under the No recommendation tab.
Reference: 

https://docs.microsoft.com/en-us/azure/security-center/security-center-adaptive-application