Answer: BLUE team
Step-by-step explanation:
A penetration test is usually performed because it is used to know the defense mechanism of the system against hackers and other unethical access to the system.
In order to defend the system from the penetration testers we have the blue team whose function is to develop algorithms and identify all the security flaws in the system so that it is not under attack from hackers.
The Blue team are generally aware o the penetration test however they do not know what mechanisms or methods the penetration team will be using.
So system upon passing the penetration test can be considered safe from outside attacks.