The answer is Diagram 4 or D
Step-by-step explanation:
A Venn diagram is a type of model that represents sets, and their relationships. Additionally, each set is usually named with a letter and symbols such as ∪ or ∩ are used to represent specific zones of the diagram. In the case of the symbol ∩, this is used to represent the intersection between two sets. This means X ∩ Z represents the intersection between X and Z. Therefore, the correct representation is the fourth diagram, which shows in red only the intersection between these two sets.