oops lol brain fart... well.. nope.. not used here.. i swear.. this one is done with one mat for the flower and one for the floor.. 2 MR area lights and thats it... nothing technical..
Ambient Occlusion is used to add depth to the scene - it's not an object, rather a function done during render to enhance the shadows. There would be an option for it somewhere in your program of choice.