Culture period of Macrobrachium rosenbergii in polyculture is:

Correct option is B

Correct Answer: (b) 8–12 months
Explanation:
→ In polyculture systems (with fishes + prawns) M. rosenbergii typically reaches marketable size over 8–12 months, depending on stocking density, feed inputs and environmental conditions.
→ Polyculture allows extended feeding regimes and complementary resource use.
Information Booster:
→ Harvest timing is adjusted to target consumer size and to coordinate with co-cultured species’ cycles.
Additional Information (Other Options):
(a): Shorter duration used in some intensified systems but not typical polyculture.
(c),(d): Far too short for grow-out to market size.