In numerical control (NC) for manufacturing, a typical NC system is composed of three major elements working together: (1) the controller (or control unit) that interprets instructions, (2) the input medium such as tape input or its modern equivalent for program data, and (3) the machine tool that physically performs the cutting or motion.

Introduction / Context:
A numerical control (NC) system automates machine motions based on coded instructions. Understanding the core components clarifies how programs become precise tool moves for milling, turning, drilling, and related operations. This question checks whether you can identify the standard building blocks of an NC setup as traditionally defined in manufacturing engineering.

Given Data / Assumptions:

• An NC system requires a unit to read/interpret part programs.
• Program instructions must reach the controller (historically via punched tape; now via modern media).
• A machine tool executes the motions commanded by the controller.

Concept / Approach:
Classic NC systems consist of (a) controller/control unit, (b) input medium (e.g., tape reader), and (c) the controlled machine (lathe, mill, drill). The controller translates program codes into axis commands and spindle/tool functions. The input medium delivers the coded program. The machine tool applies the motion to material, closing the loop between digital instructions and physical manufacturing.

Step-by-Step Solution:
Identify the logical roles: interpretation, input, and actuation.Map them to standard NC parts: controller, tape input (or equivalent), machine tool.Confirm that all three are essential in a typical NC configuration.Select the answer that includes all listed components.

Verification / Alternative check:
Modern CNC evolved from NC by replacing tape with digital storage and adding feedback; however, the architectural idea remains: controller + program input + machine tool. Manuals and textbooks consistently show these three roles in system diagrams.

Why Other Options Are Wrong:
Controller only: lacks the machine tool and input medium.Tape input only: no interpretation or actuation component by itself.Machine tool only: cannot act without instructions and control logic.None of the above: incorrect because all of the listed components are standard.

Common Pitfalls:
Confusing classic NC (tape) with CNC (digital media) and assuming the input element is irrelevant. Even when tape is replaced by memory or DNC links, the functional role of “program input” remains vital.

Final Answer:
All of the above