Which experiment involves the use of classical conditioning?

Which experiment involves the use of classical conditioning?Question 1 options:blindfolding someone and timing him to see how long he takes to find a button hidden in a roomdetermining how long it takes a person to learn how to knit if he is only allowed to watch YouTube videos of people knittingknowing 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 studentrewarding a boy for finishing his vegetables with ice cream and counting how many nights of reinforcement are required before he voluntarily eats his vegetables