The suggested answer is A, D.
SAN (Storage Area Network) and iSCSI (Internet Small Computer System Interface) are two block storage protocols supported on vSphere. SAN is a high-speed network that provides block-level access to storage, typically used in fiber channel networks. iSCSI is a protocol that uses IP-based networks to link data storage facilities, allowing for block-level access over Ethernet. The other options, SMB, NFSv4.1, and NFSv3, are file-level protocols and do not provide block storage, which is essential for vSphere environments.