(a) That's probably wrong. It is most unlikely that B would succeed. The courts have long refused to award damages for disappointment and distress resulting from a breach of contract in cases like this. There are some exceptional cases, but in commercial contracts, the rule still holds good.
The exceptional cases include those in which the contract involves the provision of enjoyment, entertainment or pleasure, such as a pleasure cruise, or holiday. In the present case, the contract is purely commercial and, although important to B, does not involve promises of enjoyment or pleasure.