The correct answer is (d) Silver iodide.
Silver iodide is a chemical compound with the formula AgI. It is a white, odorless, and tasteless solid that is soluble in ammonia and potassium iodide. Silver iodide is used in photography, photolithography, and as a cloud seeding agent.
Cloud seeding is a technique used to induce or enhance precipitation. It is done by dispersing silver iodide or other hygroscopic particles into clouds. These particles act as nuclei for water droplets to form around, and the resulting precipitation is then released to the ground.
Silver iodide is the most commonly used cloud seeding agent because it is highly effective at inducing precipitation. It is also relatively inexpensive and easy to use. However, there are some concerns about the environmental impact of silver iodide, and its use is regulated in some countries.
The other options are incorrect because they are not used for producing artificial rains. Silver chloride is used in photography and photolithography. Silver bromide is used in photography. Silver nitrate is used in medicine, photography, and electroplating.