(b) That's right. This question involves performance and breach of contract.

To discharge contractual obligations, the promisor must carry out the contractually binding promises that they have made to the promisee. The nature and extent of the required performance is determined by reference to the relevant terms. In relation to the recycled glass content, Ben said: "Our jars are made with up to 10% recycled glass." If this was a promise, Ben became obliged to deliver jars containing some percentage of recycled glass (up to 10%) to FoodCo. Taking account of the facts, Ben appears to have performed this obligation - the jars he delivered in fact contained 2% recycled glass.

It may be true that Astrid hoped for a greater percentage of recycled glass, but Ben did not guarantee, for example, to supply jars with "at least 10% recycled glass". If he had, there would have been a breach of contract, but that is not what he promised.

In conclusion, the given facts are sufficient to conclude that Ben has carried out the promise he made in relation to recycled glass. There is no breach of this term.

Answers (a) and (c) are therefore incorrect, and (b) is the best answer.