Life cycle of Ectocarpus and Fucus respectively are:

Answer: (D) Haplodiplontic, Diplontic.

Explanation:

• Haplodiplontic cycle is the life cycle that is intermediate between haplontic and diplontic.
• In this, both the haplontic and diplontic are free-living and multicellular. In diplontic life cycle, the diploid sporophyte is dominant. 
• Ectocarpus and Fucus are algae that have both haplodiplontic and diplontic life cycles.