In fluid statics, the buoyant force is the force exerted on a submerged or floating body due to the pressure difference in the fluid. The line of action of the buoyant force always passes through the centroid of the displaced fluid. This is a fundamental principle known as Archimedes' principle.
Step 1: Understanding Buoyant Force
According to Archimedes' principle, the buoyant force is equal to the weight of the displaced fluid, and it acts vertically upward. The force's line of action passes through the centroid of the displaced fluid. Therefore, the correct answer is (C).
Final Answer: \[ \boxed{\text{(C) centroid of the displaced volume of fluid by the body}} \]


A particle dispersoid has 1510 spherical particles of uniform density. An air purifier is proposed to be used to remove these particles. The diameter-specific number of particles in the dispersoid, along with the number removal efficiency of the proposed purifier is shown in the following table:
The overall mass removal efficiency of the proposed purifier is ________% (rounded off to one decimal place).