You are a global administrator in a company with a Microsoft 365 subscription with Microsoft 365 E5 licenses assigned to your users. You are using Advanced Threat Protection policies to harden your security and need to enable your helpdesk to view reports from the Security Dashboard (Security & Compliance Center - Threat Management – Dashboard). Which role should you assign your helpdesk? The solution must use the principle of least privilege.

Answer options:

A.Security Administrator
B.Reports Reader
C.Security Reader
D.Directory Reader

Correct Answer: C 
You should assign your helpdesk the role Security Reader.
The least privileged role that allows users to view reports within the Security Dashboard is “Security Reader”. 
See exhibit from Microsoft documentation: 

Option A is incorrect. This role will allow you to view the reports but is not the least privileged role. Hence it is not the correct answer.
Option B is incorrect. Reports Reader will not grant access to the security dashboard. With this role you can read sign-in and audit reports 
Option D is incorrect. Directory Reader will not grant access to the security dashboard. With this role you can read basic directory information.
Reference: 
To know more about viewing reports in the Security Center, please refer to the link below: 

https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/view-reports-for-mdo?view=o365-worldwide