Adsense Business account verification

I have a business adsense account that is associated to my sole proprietorship firm. To verify the adsense account, it is asking me for a CIN number. Now, I only have the GST number as a sole proprietorship firm. Can someone tell me if it's possible to get a CIN for sole proprietorship? 

Also, is it necessary for me to input my CIN in adsense verification for a business account? I'm sure there are other people in India who have sole proprietorship firms and are also using the adsense business account. 

Please help.

Best, 

Pranav