A

Step 1: Calculate the heat required to melt the ice.
Use the formula: \( Q = m \cdot L \)
Here, \( m = 0.5 \text{ kg} \) and \( L = 3.36 \times 10^5 \text{ J/kg} \).
\( Q = 0.5 \cdot 3.36 \times 10^5 = 1.68 \times 10^5 \text{ J} \).

Step 2: Calculate the heat lost by the water.
The specific heat formula is: \( Q = m \cdot c \cdot \Delta T \)
Here, \( m = 2 \text{ kg} \), \( c = 4200 \text{ J/kg/K} \), and \( \Delta T = 30 \text{ °C} - 0 ext{ °C} = 30 ext{ °C} \).
\( Q = 2 \cdot 4200 \cdot 30 = 252000 \text{ J} \).

Step 3: Compare the heat energies.
The heat required to melt the ice is \( 1.68 \times 10^5 \text{ J} \) and the heat lost by the water is \( 252000 \text{ J} \).
Since the heat lost by the water is greater than the heat required to melt the ice, all the ice will melt.

Step 4: Calculate the final temperature.
The remaining heat after the ice melts:
\( Q_{remaining} = 252000 - 168000 = 84000 ext{ J} \)

Step 5: Find the temperature rise of the melted ice:
For 0.5 kg of water (from melted ice), the formula is:
\( Q = m \cdot c \cdot \Delta T \)
\( 84000 = 0.5 \cdot 4200 \cdot \Delta T \)
\( \Delta T = \frac{84000}{0.5 \cdot 4200} = 40 \text{ °C} \)

Therefore, the final temperature of the mixture is: \( 0 + 40 = 40 ext{ °C} \).
Hence, the correct answer is 40 °C.