In OCI, the defining distinction is whether a subnet permits public IP address assignment to its resources. A public subnet permits public IP addresses, while a private subnet prohibits that assignment. Option B is therefore the best answer, but direct internet connectivity is not automatic merely because a subnet is public. An instance also needs a public IP address, an internet gateway, appropriate routing, and security rules that allow the traffic. Private-subnet instances can obtain outbound internet connectivity through a NAT gateway without receiving public IP addresses. Public and private subnets are not restricted to particular application roles, and public subnets do not universally require a /24 address range. Both belong within their VCN’s region. Oracle documentation: Public IP Addresses