What are the canonical forms of Boolean expressions?

Concept

A canonical form is a single, unique, fully-expanded expression for a Boolean function in which every term lists all the input variables. Because the function's truth table is fixed, each function has exactly one such expression in each canonical form, making the representation standard and unambiguous.

The two canonical forms

• Sum of Minterms (SOM): OR together one minterm for every truth-table row where the function equals 1; each minterm is an AND of all variables (in true or complemented form).

• Product of Maxterms (POM): AND together one maxterm for every row where the function equals 0; each maxterm is an OR of all variables.

Applying it to the choices

The question asks for the names of these two forms. Among the listed pairs, only Sum of Minterms (SOM) and Product of Maxterms (POM) are representation forms of a complete function. The pairs of gate/operator names (OR/XOR, NOR/XNOR) describe how to build or operate on signals, not how to write the whole function canonically.

Cross-check

SOM corresponds to the canonical Sum-of-Products (Σ of minterms) and POM to the canonical Product-of-Sums (Π of maxterms) — the two standard normal forms in Boolean algebra. So the pair Sum of Minterms and Product of Maxterms is the correct answer; the 'none of the above' and 'more than one' choices are ruled out because that pair is present and valid.