As you have asked about the National Eligibility cum Entrance Test (NEET) answer key for set z, I am giving you information about it

I want to tell you that NEET exam answer key will be releasing soon.
It will be released at its official website
However, there is a possibility that it might be delayed.
The official website of the exam is not working at the moment and the CBSE is trying to convert it for NEET-2.

An answer key is a file which contains solutions to all the questions in the examination.
It is released by the conducting body, as well private coaching and educational institutes.
The unofficial answer key is released on the day of the examination.
Hence, for NEET-1, it will be released on 26th May, 2016

Steps to get the answer key:

Go to NEET official website
Search for the NEET answer key link
Click on it and select your set
Click on the required file
You may open it
Then save it for future use