Bard Combat Inspiration: so DM must show his roll to player?

@JeremyECrawford Bard Combat Inspiration use with reaction to add the roll to AC "AFTER SEEING THE ROLL"
So DM must show his roll to player?

— Draconis (@DerynDraconis) June 22, 2016

If a player character ability relies on knowing a monster's roll, a DM may say what the roll is or show it #DnD https://t.co/sMNJOZBoe8

— Jeremy Crawford (@JeremyECrawford) June 22, 2016