A company's CEO receives an email from what appears to be a trusted source, requesting sensitive financial information for an 'urgent financial audit'. Which of the following is the BEST course of action the CEO should take to verify the legitimacy of this request?
Reply to the email and ask for confirmation that the request is legitimate.
Ignore the email as it is likely to be a scam without taking any further action.
Contact the trusted source directly using previously verified contact information to confirm the request.
Use the phone number provided in the email to call the trusted source and confirm the request.