Answer
(a) $C\lt A\lt B$
(b) $A=B=C$
Work Step by Step
(a) We know that the total weight is equal to the difference between the weight of the water in the container to depth and to the weight of fluid that is replaced by the objects. As it is given that all three water levels are equal, the value of $V_{submerged}$ for the wooden block is the greatest for $C$ because the weight and the lead mass has the greatest weight and displaces the most weight of water; followed by $A$ and $B$. Thus, the required rank in order of increasing water weight is $C\lt A\lt B$.
(b) We know that the water levels are the same and the pressures at the bottom of each container $(P_{atm}+\rho gh)$ are the same. Hence, the weight of each of the containers is the same because the force at the depth is the same. Thus, we can rank the containers as $A=B=C$.
