Q.Convert $Y = (AB + C)$ into its canonical SOP form

A canonical (standard) SOP form must have every product term containing all three variables A, B and C. Each term is expanded by ANDing it with the OR of any missing variable and its complement. …

[!TLDR]

Expand $Y = AB + C$ by filling in the missing variables so that every product term holds all of A, B and C, giving the five-minterm canonical SOP.

In a canonical (standard) SOP expression each AND term must contain every input variable, in either complemented or un-complemented form. We use the identity $(X + \overline{X}) = 1$: a term is ANDed with $(X + \overline{X})$ for each missing variable X, then distributed.

Term $AB$: variable C is missing, so AND with $(C + \overline{C})$:

Term $C$: both A and B are missing, so AND with $(A + \overline{A})(B + \overline{B})$: …