PROJECTION and SELECTION are the unary operations in relational algebra. Unary operations are those operations which use single operands. Unary operations are SELECTION, PROJECTION, and RENAME.

As in SELECTION relational operators are used for example – =,=, etc.

In relational algebra, unary operations are operations that operate on a single relation. The correct answer would typically include operations like Selection (σ), Projection (π), and Rename (ρ). These operations manipulate or transform a single relation.