Question 289General Subjects - Assistant Engineer

The correct answer is A) the use of internal threads. The standard blueprint symbols above the letters "A", "B", and "C" in the illustration GS-0036 indicate the use of internal threads. This is a common drafting convention used to represent threaded holes or openings in engineering drawings and blueprints. The other answer choices are incorrect because: B) hole tolerance refers to the allowable variation in the size of a drilled hole, C) finished diameter indicates the final size of a part or feature, and D) interference fit refers to a tight mechanical connection between two mating parts, not the use of internal threads.