Answer Description
Setting up a BIOS/UEFI password is the only option that would mitigate the threat from a user booting from another device (though it can often be reset by removing the CMOS battery). Data encryption, disabling admin accounts and only allowing trusted sources are all operating system level configurations and would not apply prior to booting to an OS.
Wikipedia
For IBM PC compatible computers, BIOS ( BYOS, an acronym for Basic Input/Output System and also known as the System BIOS, ROM BIOS or PC BIOS) is non-volatile firmware used to perform hardware initialization during the booting process (power-on startup), and to provide runtime services for operating systems and programs. The BIOS firmware comes pre-installed on a personal computer's system board, and it is the first software run when powered on. The name originates from …
BIOS - Wikipedia, the free encyclopedia