Step 1: Understanding osmotic pressure.
The osmotic pressure \( \Pi \) of a solution is given by the formula:
\[
\Pi = \frac{nRT}{V}
\]
where \( n \) is the number of moles of solute, \( R \) is the universal gas constant, \( T \) is the temperature, and \( V \) is the volume of the solution. Osmotic pressure is directly proportional to the number of moles of solute per volume.
Step 2: Calculating the osmotic pressure for solution A.
For solution A, the number of moles \( n_A \) of protein is:
\[
n_A = \frac{1}{50000} = 2 \times 10^{-5} \, \text{mol}
\]
The osmotic pressure of solution A is:
\[
\Pi_A = \frac{n_A RT}{V_A} = \frac{2 \times 10^{-5} \times 0.083 \times 300}{0.5} = 9.96 \times 10^{-4} \, \text{bar}
\]
Thus, \( x = 9.96 \times 10^{-4} \).
Step 3: Calculating the osmotic pressure for solution B.
For solution B, the number of moles \( n_B \) of protein is:
\[
n_B = \frac{2}{50000} = 4 \times 10^{-5} \, \text{mol}
\]
The osmotic pressure of solution B is:
\[
\Pi_B = \frac{n_B RT}{V_B} = \frac{4 \times 10^{-5} \times 0.083 \times 300}{1} = 9.96 \times 10^{-4} \, \text{bar}
\]
Thus, \( y = 9.96 \times 10^{-4} \).
Step 4: Calculating the osmotic pressure of the resultant solution.
When solutions A and B are mixed, the total number of moles is \( n_A + n_B = 6 \times 10^{-5} \). The total volume is \( V_A + V_B = 1.5 \, \text{L} \). The osmotic pressure of the resultant solution is:
\[
\Pi_{\text{total}} = \frac{(n_A + n_B)RT}{V_A + V_B} = \frac{6 \times 10^{-5} \times 0.083 \times 300}{1.5} = 19.92 \times 10^{-4} \, \text{bar}
\]
Thus, \( z = 19.92 \times 10^{-4} \).
Final Answer: (B) \( 9.96 \times 10^{-4}, 9.96 \times 10^{-4}, 19.92 \times 10^{-4} \)