Which experiment involves the use of classical conditioning? blindfolding someone and timing him…

Which experiment involves the use of classical conditioning?
blindfolding someone and timing him to see how long he takes to find a button hidden in a room
determining how long it takes a person to learn how to knit if he is only allowed to watch YouTube videos of people knitting
knowing that a student fears exams, the instructor wears a bright red shirt only on exam day, every exam day, to see how long it is before the red shirt becomes an object of fear to the student
rewarding a boy for finishing his vegetables with ice cream and counting how many nights of reinforcement are required before he voluntarily eats his vegetables