Answer:
A) Because the contract specified what would happen in the case of a mistake,the sale price will not be altered.
Step-by-step explanation:
When a contract is formed between different parties there is an offer and acceptance of the terms of the contract.
In this instance the agreement was made after an appraisal of the violin. It was agreed that even if the appraisal was found to be faulty the price would not change from $10,000 agreed upon.
Therefore when Rachael realised the price is $5,000 after one month, the price will not change because the contract specified what would happen in the case of a mistake, the sale price will not be altered.
Even when there is no appraisal and the buyer accepts terms, the error of not properly validating the price of the product is on the buyer. The onus is on the buyer to establish the right price for the good.