can i edit "NO" OPTION TO "YES"whether son of JCO/NCO/other Rank officers and studying in Sainik Military school
Assuming from your question that you are currently studying in a Sainik school if so then you can simply go to the Main office or admission block and ask them to rectify that mistake by providing all the neccessary documents i.e Service letter of your father and some other documents.
If not studying in a sainik school and willing to go then just tell them this at the time of admission and provide them with the documents.
please give answer key of class 4 NCO set A 2019,or how will i get it?
For now, the motion institute has released the unofficial answer key for class 5 to 10. The official answer keys will be released soon by January 2020.
You can get the answer keys of 2018 for class 4 from the link given below:
Hope this helps!