Explanation:

- Option 1: Silver iodide and potassium iodide

- Correct. Artificial rainfall or cloud seeding often involves using silver iodide, sometimes accompanied by other substances like sodium chloride or potassium iodide, to encourage precipitation.

- Option 2: Silver nitrate and potassium iodide

- Incorrect. Silver nitrate is not typically used in cloud seeding for artificial rainfall.

- Option 3: Silver iodide and potassium nitrate

- Incorrect. While silver iodide is used, potassium nitrate is not standard in cloud seeding.

- Option 4: Silver nitrate and potassium chloride

- Incorrect. Both silver nitrate and potassium chloride are not conventional choices for inducing artificial rainfall.

- Correct Answer: Option 1, Silver iodide and potassium iodide