Haplo-diplontic life cycle is a type of life cycle that involves both haploid and diploid phases in the life cycle of an organism. In this life cycle, the organism alternates between a multicellular haploid phase and a multicellular diploid phase.

The correct group of organisms that completely exhibit a haplo-diplontic life cycle is option 'C', which includes the following organisms: funaria, salvinia, eqisetum, polysiphonia, kelp, and riccia.

Here is an explanation of why this group of organisms fits the criteria of a haplo-diplontic life cycle:

1. Funaria: Funaria is a moss that exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte, which produces haploid spores.

2. Salvinia: Salvinia is an aquatic fern that also exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the diploid sporophyte, which produces haploid spores. These spores germinate to form the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte.

3. Equisetum: Equisetum, also known as horsetail, exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the diploid sporophyte, which produces haploid spores. These spores germinate to form the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte.

4. Polysiphonia: Polysiphonia is a red algae that exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the diploid sporophyte, which produces haploid spores. These spores germinate to form the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte.

5. Kelp: Kelp is a type of brown algae that exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the diploid sporophyte, which produces haploid spores. These spores germinate to form the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte.

6. Riccia: Riccia is a liverwort that exhibits a haplo-diplontic life cycle. The dominant phase of the life cycle is the haploid gametophyte, which produces haploid gametes. Fertilization between the male and female gametes results in the formation of a diploid sporophyte, which produces haploid spores.

In conclusion, the group of organisms in option 'C' completely exhibits a haplo-diplontic life cycle. Each organism in this group alternates between a multicellular haploid phase and a multicellular diploid phase in