B is correct. Global macro funds employ a highly active asset allocation strategy, taking bets on a diverse range of risk factors such as equity, interest rates, commodities, and currencies based on macroeconomic trends. Because of their broad and unconstrained mandate across various asset classes globally, their return streams often resemble those of a broadly diversified hedge fund portfolio.

A and D are incorrect as managed futures and trend followers typically focus specifically on momentum strategies in futures markets rather than broad asset allocation bets. C is incorrect as merger arbitrage focuses on event-driven pricing inefficiencies between merging companies, not broad asset allocation.