The correct answer is A. reformation.
A reformation is a change for the better, while a deterioration is a change for the worse. An amendment is a change to a law or document, while an improvement is a change that makes something better. A revision is a change to something that has been written or published.
In the sentence “There was a marked deterioration in his condition,” the word “deterioration” means a change for the worse. This is evident from the fact that the word “marked” is used, which suggests that the change was significant. The other options do not make sense in the context of the sentence.
A reformation is a change for the better. This could be a change in someone’s behavior, such as a person who stops smoking or drinking. It could also be a change in someone’s beliefs, such as a person who converts to a new religion.
An amendment is a change to a law or document. This could be a change to the Constitution, such as the 13th Amendment, which abolished slavery. It could also be a change to a contract, such as a change to the terms of a lease.
An improvement is a change that makes something better. This could be a change to a product, such as a new version of a software program. It could also be a change to a service, such as a new way of delivering packages.
A revision is a change to something that has been written or published. This could be a change to a book, such as a new edition of a classic novel. It could also be a change to an article, such as a correction to a factual error.