What specific technical capability did ISRO demonstrate in the first Integrated Air Drop Test (IADT-1) for the Gaganyaan programme?

The IADT-1 test demonstrated the parachute-based deceleration system, a critical element for ensuring the safe landing of the crew module during the Gaganyaan human spaceflight programme. The brief explains that in actual missions, parachutes deploy after re-entry, subsequent to deceleration by heat shields and drogue parachutes. The air-drop specifically tests the parachute sequence and deceleration performance essential for human-rating. Options (a), (c), (d), and (e) describe other types of tests or capabilities not stated as part of IADT-1 in the provided information.