Which of the following scenarios reflects the consistency property at work?

a$.)$

$1.$ A transaction has five SQL requests.

$2.$ The first two successfully completed.

$3.$ The third one failed.

$4.$ The entire transaction is committed.

b$.)$

$1.$ A transaction updates a chunk of data in a database and commits it$.$

$2.$ During the commit of the transaction, the system fails.

$3.$ Once the database is brought back online, the data is updated and written.

c$.)$

$1.$ A user attempts to remove a product from the product table.

$2.$ The product has been purchased by another individual and exists in the order table.

$3.$ The transaction is denied due to a foreign key constraint.

d$.)$

$1.$ Multiple transactions are being executed separately but in parallel.

$2.$ All transactions are carried out and executed as if they were one transaction.

$3.$ No transaction will affect another transaction.