Explanation:

- The alloy consists of 30% aluminum.

- To find the total weight of the alloy needed to contain 300 grams of aluminum, use the formula:

$$

\text{Total Alloy Weight} = \frac{\text{Amount of Aluminum}}{\text{Percentage of Aluminum in Alloy}}

$$

- Substitute the values:

$$

\text{Total Alloy Weight} = \frac{300 \text{ gm}}{0.3} = 1000 \text{ gm} = 1 \text{ kg}

$$

- Option 1: 0.8 kg – This is too low. It would contain only 240 grams of aluminum.

- Option 2: 1 kg – This is correct. It contains exactly 300 grams of aluminum.

- Option 3: 1.2 kg – This is too high. It would contain 360 grams of aluminum.

- Option 4: 0.6 kg – This is too low. It would contain only 180 grams of aluminum.