How many B-II fire extinguishers must be in the machinery space of a 175-foot long fishing vessel propelled by engines with 4000 brake horsepower?

Correct Answer: Option C — 4

46 CFR 28.155 dictates fire extinguisher requirements for fishing vessels based on length and propulsion. For a 175-foot vessel with 4000 horsepower, the machinery space requires a specific number of B-II extinguishers to ensure adequate coverage for potential fuel or oil fires, which in this case is four.