${?}_{{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{a}nd{?}_{?}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}\text{d}\text{e}\text{f}\text{i}\text{n}\text{e}\text{f}\text{o}\text{r}\text{e}\text{i}\text{g}\text{n}\text{k}\text{e}\text{y}\text{t}\text{h}\text{a}\text{t}\text{e}\text{s}\text{t}\text{a}\text{b}\text{l}\text{i}\text{s}\text{h}\text{e}\text{s}\text{r}\text{e}\text{l}\text{a}\text{t}\text{i}\text{o}\text{n}\text{s}\text{h}\text{i}\text{p}\text{s}\text{b}\text{e}\text{t}\text{w}\text{e}\text{e}\text{n}\text{t}\text{a}\text{b}\text{l}\text{e}\text{s}\text{.}}$

Question $25$ options:

Identifier, primary key.

Identifier, foreign key.

Attributes, primary key.

Attributes, foreign key.