∴ their buoyancy f 1 > F2,
∫A sinks and B hangs.
∴G A > F 1,G B =F2。
∴G a > g b,
(2)∫A sink, B float, C float,
∴ ρ A > ρ 1,ρ B =ρ2,ρ C < ρ 3
∵ρ 1=ρ2>ρ3,
∴ ρ A >ρB >ρC,
(3)∵V B > V C, as can be seen from the figure, V B > V C.
∵ ρ 2 >ρ3.
Their buoyancy F2 > F3, both balls float, and their buoyancy is equal to their own gravity.
∴G b > British c,
∴G A > uk b > uk c,
So choose ad.