As per the information available on internet, Allen Kota don't publish any answer key for GATE examination. The institute releases the answer key for various examination such as NEET, JEE MAINS and Advanced, KVPY etc.

For GATE answer key visit:

https://engineering.careers360.com/articles/gate-answer-key

For PYQ's you may visit the official website:

https://gate.iitkgp.ac.in/old_question_papers.html

I hope this helps.

I hope this helps.