Answer:C
Explanation:
Partially submerged block along with vessel is accelerated upwards .
Initially the block weight is supported by buoyant force such that it is in equilibrium.
when the system start accelerating upwards then the effective gravity will be
g+a where a is the acceleration of the system.
so only net gravity is increased so block will not ascend or descend.
Mathematically
[tex]F_b=weight[/tex]
[tex]\rho _L\cdot V\cdot (g+a)=m(g+a)[/tex]
where [tex]\rho _L=[/tex]density of liquid
V=volume of object inside the water