The words in the brackets are telling the actors what to physically do, meaning it would be a stage direction.
It isn't dialogue because that is a conversation between two people.
It isn't dialect because that is how a person speaks. There is no speaking in the brackets.
It isn't narration because it isn't spoken allowed for the audience.
It isn't a description because that is too broad a term more often used for emotions.
The answer is number two I think
The Cornell method has been proven to be very useful & is used throughout high school/college education. color coding notes & making them aesthetically pleasing can impact your focus on the info. flash cards or repetition is helpful in the memory process