Regarding the scenario where a FortiSwitch did not reboot after the authorization process while the other devices did, the most likely cause, given the configuration settings in the exhibit, is:
The management mode was set to use FortiLink mode (Option B): If the FortiSwitch was already configured to use FortiLink for its management mode, it may not require a reboot to complete the authorization process as its management interface settings are already aligned with FortiLink requirements. This is unlike switches that might be transitioning from a standalone or another management mode, which would typically require a reboot to apply new management settings fully.
Reference:
FortiLink mode specifically tailors FortiSwitch to be managed via a FortiGate device, integrating its operation into the wider security fabric without needing a reboot if it is already set to this mode before authorization. This contrasts with other management modes where transitioning to FortiLink could necessitate a system restart to initialize the new configuration.

The native VLAN is implicitly part of the allowed VLAN on the port (C): On a managed FortiSwitch port, the native VLAN, which is the VLAN assigned to untagged traffic, is implicitly included in the list of allowed VLANs. This means it does not need to be explicitly specified when configuring VLAN settings on the port. This configuration simplifies VLAN management and ensures that untagged traffic is handled correctly without additional configuration steps.

QSFP+ transceiver (A): The QSFP+ (Quad Small Form-factor Pluggable Plus) transceiver is designed to handle 40G data rates and can be used to split a 40G port into multiple 10G connections. This type of transceiver supports such configurations, making it suitable for high-density applications where multiple 10G connections are derived from a single 40G port, thereby maximizing the utilization of the port and the fiber infrastructure.

When FortiGate exports configuration settings to a managed FortiSwitch stack with sampling mode set to "perimeter is true," the behavior is:
B . FortiGate configures FortiSwitch to perform ingress sampling on all switch interfaces, except ICL and ISL interfaces. This setting ensures that all incoming traffic on normal operational ports is sampled for monitoring and analysis purposes, but it excludes the inter-chassis link (ICL) and inter-switch link (ISL) interfaces from sampling. These exclusions are typically made to prevent the duplication of sampled data and to reduce unnecessary load on the monitoring system, as these links often carry traffic already monitored at other points.
Options A and D are incorrect because they either generalize the sampling across all interfaces without exceptions or incorrectly specify egress sampling on management interfaces. Option C is also incorrect as FortiGate can modify existing sampling settings to fit the perimeter-based configuration requirement.