The weight of a balloon is W1 when empty and W2 when filled with air. Both are weighed in air by the same sensitive spring balance and under identical conditions.
A W1=W2, as the weight of air in the balloon is offset by the force of buoyancy on it.
B W2C W2>W1, as the air inside is at a greater pressure and hence hs greater density than the air outside.
D W2=W1+ weight of the air inside it.