In the context of Bash scripting for system automation, the killproc command is often used to stop a process.
The correct option to complete the script for a Chef Client reload would involve sending a HUP (hang-up) signal to the Chef Client process, which is typically done to cause the process to reload its configuration without stopping the service. The command killproc -p $pidfile $exec --HUP would send the HUP signal to the process identified by the pidfile, which is the expected behavior for a Chef Client reload on a system reset.
References := For a detailed explanation and official documentation, the Cisco Data Center Core Technologies source book or study guide should be consulted, as well as the official Chef documentation which provides information on system and service management commands.