Which abbreviation is often used to remind someone to read the instructions thoroughly?

The abbreviation RTFM stands for "Read The F***ing Manual." It is a colloquial and somewhat humorous way to emphasize the importance of reading instructions or documentation carefully before attempting to use a product or service. This phrase is often used in technical contexts, especially in programming and online communities, to encourage individuals to look for answers in user manuals, guides, or documentation rather than seeking help from others without first trying to understand the provided resources.

The other abbreviations serve different purposes: FYI means "For Your Information," which is used to share information without expecting a response; MRAU is not a widely recognized abbreviation in this context; and IIRC means "If I Remember Correctly," used when one is unsure about the information being recalled. Thus, RTFM directly relates to the action of reading instructions, making it the most appropriate choice for this context.