GST on Extra Classes - Goods and Services Tax - GST

Respected experts, As per para No. 2.1 of Circular No. 85/04/2019 dated 01.01.2019 ,wherein it has been mentioned that Supply of all services by an educational institution to its students, staff and faculty is exempt under Notification No. 12/2017- CTR dated 28.06.2017 Sr. No. 66. 1. Please guide whether all services cover preparation of NDA, IIT, PMT various competitive entrance exam etc. on additional consideration or these activities are taxable. 2. Whether extra classes provided by schools after school hours are taxable or exempted ? 3. Whether the supplies done by school other than education like sale of bus, furniture or other school articles are taxable under gst?