Hello
If your query is about NEET exam, to challenge the answer key candidates were required to pay a sum of Rs. 1000. After successful payment, candidates had to download/print the key challenge receipt.
Since it is late to answer this query, I hope your problem was solved. Do let us know if you have any other queries.
Good Luck!
Yes sir i understand your query regarding this as i would like to give you a brief about this through the official article of career 360link as follows:
https://www.google.com/amp/s/medicine.careers360.com/articles/neet-counselling/amp
If you still have any query ask me in comments
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