The best option for the security analyst to perform is to contact the security department at the business partner and alert them to the email event. The email appears to be a phishing attempt that tries to trick the employees into revealing their login credentials by impersonating a legitimate sender. The security department at the business partner should be notified so they can investigate the source and scope of the attack and take appropriate actions to protect their systems and users. Verified Reference: https://www.comptia.org/training/books/casp-cas-004-study-guide , https://us-cert.cisa.gov/ncas/tips/ST04-014