Mithali, a financial analyst, is preparing data to engage in a data analysis project to predict revenue for the next period based on environmental considerations. She is currently reviewing the tables to validate inter$-$table rules for referential integrity. Which of the following is true about referential integrity?

$$ The primary and foreign key fields must have the same name.

$$ All values in a foreign key should also exist as values in the corresponding primary key.

$$ The primary and foreign key fields can have different data types.

$$ The primary key must be single$-$valued, but the foreign key can be multi$-$valued.