Why is the Alai Darwaza important in the history of Indo-Islamic architecture?

It shows mature use of the true arch and dome is the defensible answer to this advanced Medieval History question. Built by Alauddin Khalji in 1311, the Alai Darwaza displays accomplished true arches, a true dome, red sandstone, white marble inlay and refined geometric decoration. The monument must be read through patronage, construction technique and chronology. Indo-Islamic buildings developed by combining arcuate forms, local craftsmanship, stone carving and changing imperial requirements; a visually plausible option is not automatically the historically correct patron or feature. The distractors need separate rejection: It introduced rock-cut caves belongs to a different institution, context or chronology; It was the first wooden palace does not perform the function described in the stem; and It contains Ashokan inscriptions fails the required association. The wording of “Why is the Alai Darwaza important in the history of Indo-Islamic architecture?” is deliberately specific, so the candidate should isolate its operative clue before recalling names. A useful method is to construct a two-step link from the tested term to its function and then from that function to the relevant ruler, text, monument or region. The fact is significant beyond one MCQ because it reveals how medieval institutions worked in practice and how historians classify the surviving evidence. — It shows mature use of the true arch and dome”, but also remember the factual reason stated above.