Most cultivated seaweed globally is:

Correct option is B

Correct Answer: (b) Laminaria
Explanation:
→ Laminaria / Saccharina (kelp) species rank among the highest by global production tonnage, especially in East Asia (China, Korea, Japan).
→ Their large biomass and use in food, alginate and hydrocolloid industries make them the most cultivated.
Information Booster:
→ Seaweed farming statistics show kelps (Laminaria/Saccharina) and nori (Porphyra) as top commodities, with kelps dominating by wet weight.
Additional Information (Other Options):
(a) Porphyra (nori) is hugely important but less in wet tonnage than kelp; (c)/(d) are cultivated but on a smaller commercial scale.