A company is currently planning to set up resources as part of its Azure subscription. They are looking at different security options that can be used to secure their Azure environment. 
Which of the following could be used for the following requirement? 
“Provide the ability to restrict traffic into Azure virtual machines.”

Answer options:

A.Azure Key Vault
B.Azure Network Security Groups
C.Azure Multi-Factor Authentication
D.Azure DDoS Protection

Answer - B
This can be accomplished with the help of Network Security Groups. 
The Microsoft documentation mentions the following. 

Option A is incorrect since this is used to store secrets, certificates and keys. 
Option C is incorrect since this is used to provide an extra level of security during user authentication. 
Option D is incorrect since this is used to protect against Distributed denial of service (DDoS) attacks. 
For more information on network security, please visit the below URL- 

https://docs.microsoft.com/en-us/azure/virtual-network/security-overview