In DOS-era terminology, what does the acronym TSR stand for with respect to small utilities that remain active after execution?

Introduction / Context:
TSR programs were a hallmark of DOS environments. They allowed small utilities (such as pop-up calculators, key enhancers, or clipboard tools) to remain in memory after execution and be invoked later via hotkeys, despite DOS being a single-tasking OS.

Given Data / Assumptions:

• Acronym expansion is requested.
• DOS memory model and interrupt-driven activation are implied.
• TSRs hooked interrupts (keyboard/timer) to trigger functionality on demand.

Concept / Approach:

TSR stands for 'Terminate and Stay Resident' (commonly written without 'and' in informal abbreviations), meaning the program terminates normally to DOS but leaves a portion resident in RAM, ready to resume service when triggered. This provided pseudo-multitasking for simple utilities without a full multitasking kernel.

Step-by-Step Solution:

Verification / Alternative check:

DOS development references and interrupt lists document TSR mechanics and memory footprints extensively, using the phrase 'Terminate and Stay Resident'.

Why Other Options Are Wrong:

• Other expansions are invented and not used historically.
• None of the above is incorrect because a correct expansion is present.

Common Pitfalls:

• Assuming TSRs provide full multitasking; they only offer limited resident functionality.

Final Answer:

Terminate Stay Resident.