Final answer:
The specific Surah revealed just prior to the declaration of the Imamat of Hazrat Ali is not historically documented and is subject to theological interpretation.
Step-by-step explanation:
The Surah revealed just prior to the declaration of the Imamat of Hazrat Ali is not specified in historical sources and is a matter of theological interpretation rather than historical record. The declaration of Imam Ali's leadership is an event of great significance in Shia Islam. However, when it comes to the question of which Surah was revealed prior to this event, it is important to note that the revelations of the Quran were not always tied directly to specific historical events and the order of revelation is different from the order of the Surahs in the current compiled form of the Quran.
As for the options provided: Al-Fatiha is often considered the first complete Surah revealed to the Prophet Muhammad, Al-Adiyat is a Surah that discusses themes related to the Hereafter and human ingratitude, Al-Ankabut (The Spider) addresses tests of faith among other themes, and Al-Qadr (The Power) describes the night of the Quran's revelation. These Surahs have their own unique places and themes within the Quran but there's no specific commonly agreed upon historical tie to the declaration of Imam Ali's Imamat next to them.