Which of the following are true about ER diagrams? Select all that apply.

Group of answer choices

Every entity set must have at least one attribute marked as a key

Every relationship set must have at least one attribute marked as a key

The side of a relationship set $($left or right$)$ that an entity set is drawn on is important

The side of a relationship set $($left or right$)$ that a cardinality annotation is drawn on is important