Father, age 67, owns 84% of the common shares of Opco. Mother owns 8%. The remaining 8% is owned by their son, age 22, who works full-time in the business with Father. Mother has no involvement in any aspect of the business. Opco is in the business of manufacturing furniture. In the current year, Opco paid dividends to Father, Mother, and Child. Income tax reference: ITA 120.4(1), (1.1).

Explain why the dividends received by Father, Mother, and Child are not subject to tax on split income.