Unlock this challenge:
What is the primary advantage of passing an object that implements MailerInterface to the FriendHarvester class, as opposed to using a specific class like SmtpMailer?
MailerInterface
FriendHarvester
SmtpMailer
It reduces the need for interfaces in PHP.
It makes the code more complicated and harder to maintain.
It allows the FriendHarvester class to accept any mailer type that implements the interface.
It enforces stricter code standards.
