Answer:
Object A, by 0.5 cubic centimeter
Step-by-step explanation:
Density (d) is given by :

m is the mass of an object
V is its volume
For object A:

...........(1)
For object B:

...........(2)
From equation (1) and (2) it is clear that volume of object A is greater by 0.5 cm³. So, the correct option is (b) "Object A, by 0.5 cubic centimeter".