Where does Email Security.cloud reside when it is deployed?

Where does Email Security.cloud reside when it is deployed?

A. Office 365

B. Company Private Cloud
C. Wide Area Network
D. Local Area Network

Reference: https://www.it-klinika.rs/blog/uporedna-analiza-koliko-je-symantec-dobar-u-zastiti-vaseg-imejla/email-security-cloud-en.pdf