pressure pressure on the container which is correct answer

The above left is a cylinder containing $1$ kg of water at $0$ °C. Then gases A and B nonreactive to each other are added. After enough time passes, as the picture on the right shows, the height h is stabilized with partial pressures of both gases being $0.5$ atm. The solubilities of gas A and B at 0°C and 1 atm are

$2 \times 10^{-3} g/100g$ of water

$4 \times 10^{-3} g/100g$ of water

respectively. If the formula weight of B is twice as much as that of A and the mass of the piston is negligible, which of the following statements is correct?

a) The dissolved weight of gas B is twice as much as that of gas A. b) The number of moles of gas A and B, when added initially, were not the same. c) The molalities of gas A and B, after being dissolved in the water, are the same.