how could I answer this question? thanks

Assessment 4: Case study - problem-solving exercise

Scenario

The SuperFood Supermarket is promoting a new range of sparkling wine. As part of the promotion it has on display in the wine section the following notice.

Buy 2 bottles of Sparkglo

(The wine that glows in the glass)

For $15 each

And get

a set 6 champagne glasses FREE!

Jo takes two bottles of Sparkglo from the shelf to the checkout where they are put through the bar code reader. When Jo asks for the wine glasses the check-out operator says that the promotion is finished, as the supermarket has no more glasses.

Required:

Using the principles of the law of contract formation, explain with reasons whether the Superfood Supermarket is legally bound to supply the 6 champagne glasses.