This question is about naming a specific bilateral naval exercise between India and Australia. Vajra Prahar and Cobra Gold can be dismissed right away, since one is an India-US exercise and the other is a Thailand-US led drill, neither involving Australia. Ausind 19 is also wrong, simply because it is not the exercise's actual name.
The correct name is AUSINDEX, and its third edition, held at Visakhapatnam in 2019, brought the Indian and Royal Australian navies together for drills in anti-submarine warfare and maritime surveillance.
So the correct answer is Ausindex 19.
AUSINDEX has run as a recurring bilateral naval exercise between India and Australia, and the way to answer this question is to first isolate which option is even part of that particular exercise series before worrying about the edition number or location.
Filtering first by which exercise series each option belongs to leaves only one candidate standing, and its details match exactly.
Therefore, the correct answer is Ausindex 19.