Concept:Identify the prayer not linked to the period between Isha and Fajr.Explanation:Isha and Fajr mark the beginning and end of the night.Shaf'i, Witr, and Tahajjud are prayers that can be offered during this night period.Istisqa is a special prayer for rain, not a night prayer.Hence, Istisqa is not observed between Isha and Fajr.Answer:D. Istisqa