The correct answer is option-1, Whittaker. The five-kingdom classification system was proposed by Robert Whittaker in 1969. This system classified living organisms into five categories or kingdoms based on their characteristics and evolutionary relationships. The five kingdoms are:

1. Monera: Comprised of prokaryotic organisms such as bacteria and cyanobacteria.

2. Protista: Consists of eukaryotic organisms that are mostly single-celled, including protozoans and algae.

3. Fungi: Includes multicellular eukaryotic organisms such as mushrooms, yeasts, and molds.

4. Plantae: Comprises multicellular, photosynthetic eukaryotes like plants.

5. Animalia: Comprised of multicellular, heterotrophic eukaryotes, which are animals. This classification system provided a more comprehensive and accurate understanding of the diversity of living organisms.