Concept:Salatul istiqa is the special Islamic prayer offered to ask Allah for rain.Explanation:Salatul istiqa is performed when there is drought.Drought means a long period without rainfall, causing dryness and water shortage.During such times, Muslims pray to Allah to send rain and relieve the land.Therefore, the correct condition for performing Salatul istiqa is drought, not eclipse, rainstorm, or earthquake.Answer:C. Drought