∴VA:VB=(LA)3:(LB)3= 1:8，

Bottom area ratio:

SA:SB=(LA)2:(LB)2= 1:4，

∫G = mg =ρVg, AB density is the same,

∴ ga: GB = ρ vag :ρvbg = va: VB =1:8, so b is wrong;

∫p = FS = GS，

∴ Pa: Pb = GASA: GBSB =11:84 =1:2, so d is wrong;

η A =GAh？ (GA+？ G move) h=GAGA+G move,

ηB = GBh(G b+ G move)h = GBGB+G move = 8G8GA+G move

√ηA:ηB = 4 1:48，

That is Gaga+gmove: 8Ga+gmove = 41:48,

Simplify:

Ga: g move = 5: 1，

∴ GB: G = 40: 1, so C is wrong;

When a rises at a constant speed in the water,

η=(GA？ F floating) h? (GA？ F floating+? G moving) h

=GA？ F floating GA? F floating +G moving

=GA？ F floating GA? F floating+15GA

=GA？ F floating 65GA? F floating

=ρAVAgρ water VAg65ρAVAgρ water VAg=80%,

Solution: ρA=5× 103kg/m3, so A is correct.

So choose a.