B
Functional mean, of or having a special activity, purpose, or task; relating to the way in which something works or operates.
nothing........................................
Subliminal messages are stimuli that lie below our threshold of conscious awareness. Because they fall below the absolute threshold level (ATL), we can't perceive a subliminal message, even if we're looking for it. That's important. ... A stimulus can influence us subconsciously without being subliminal.
Use your emergency brake immediately.