Final answer:
An addendum is used to transmit changes to an instruction or, under certain circumstances, a notice. It is the correct answer for the medium that communicates these type of updates to a previously existing document.
Step-by-step explanation:
The question relates to the medium used to transmit changes to an instruction or, in certain situations, a notice that needs to be communicated. The correct answer to this question is:b) Addendum.
An addendum is typically used in a formal context to make alterations or additions to a previously existing document, contract, or agreement without invalidating the original content. It serves to transmit changes about a given instruction or situation that may have developed after the original document was created or communicated. In contrast, a memorandum (also known as a memo) is a type of document used for internal communication within an organization, an amendment is a small change or addition designed to improve a text, document, or bill, and a revision notice would refer more broadly to notifications of alterations made to a particular set of documents or instructions.