(a) That's right. Contracts are likely to be treated as indivisible when what was contracted for was a 'single thing in a business sense'. In the present case the various items bought do not seem likely to have been bought as components of a single thing in any sense. They are just separate things needed by a farmer, bought at the same time. In addition, the price of each item was agreed separately. In these circumstances, it is likely that the purchase of each item will be treated as a separate (divisible) contract. In relation to the irrigation pipes and grass cutter, B has performed his obligations (delivery) and would be entitled to claim payment of the agreed price for each.

Obviously, B has failed to perform his obligations in relation to the fencing wire.