Martin is writing a document that describes in general terms how to secure embedded operating...

A Guideline (A) provides general recommendations and best practices without mandatory requirements or detailed instructions.

Procedures (B) are step-by-step instructions for specific tasks.

Standards (C) specify mandatory requirements, often with measurable criteria.

Policies (D) establish high-level organizational directives and rules.

Martin’s document provides general, non-mandatory advice applicable broadly, fitting the definition of a guideline.