Final answer:
When a buyer is in breach of a contract for the sale of goods, the seller may withhold delivery of all undelivered goods if the breach regarding one installment substantially impairs the value of the whole contract.
Step-by-step explanation:
When a buyer is in breach of a contract for the sale of goods, the seller may withhold delivery. In this situation, option B is true. When the breach regarding one installment substantially impairs the value of the whole contract, all undelivered goods may be withheld. This means that if the breach by the buyer significantly affects the value of the entire contract, the seller has the right to withhold delivery of all undelivered goods.