Mia owns a successful caf in Dunedin called Caf Tropical. She makes all her own food and also sells coffee, which, despite COVID-19 lockdowns, provided her with an income in excess of $100,000 in 2020-21. She has recently changed her coffee provider to one that sells 'fair trade' coffee. Cafme Limited (a Dunedin based coffee bean roaster) purchases raw coffee beans from an overseas supplier for $65,000 (excluding GST). Cafme then grind the beans and package them for sale to cafs with a 20% mark-up. Mia purchases all of Cafme coffee to produce beverages in her caf. When the coffee is sold to customers, Mia places a 40% cent mark-up on her purchase price.

(a) Briefly explain Mia's GST obligations (New Zealand) for her business. No calculations are required.

(b) Calculate the GST obligations for Cafme Limited, Caf Tropical, and the final consumers for the 2020-21 tax year, assuming that all supplies are taxable. In your answer, provide the selling price including GST, the output GST, the input GST, and the net GST payable.