2. Tree diagram.
A tree diagram is used to represent a probability space of a compound event. A tree diagram always starts at a single node, and then branches out and is used in strategic decision making, valuation or probability calculations. Therefore, the correct option is option 2.
Attached you will find an example of a tree diagram.
A tree diagram is an organizing tool used to determine the sample space of a compound event.
A compound event is an event that has more than one possible outcomes