In computer aided design and drafting, the abbreviation CAD commonly stands for which of the following?

Introduction / Context:
CAD is a widely used acronym in engineering, architecture and design industries. It refers to software tools and systems that help professionals create precise drawings, models and plans. This question checks whether you know the correct expansion of CAD, which is a straightforward but frequently tested fact in computer and technical general knowledge sections. Recognising the full form is essential for understanding job descriptions, course titles and software names in design fields.

Given Data / Assumptions:

• The abbreviation in question is CAD.
• The context is design and computer technology.
• Options provide several possible expansions, including Common, Computer, Complex and Communication Aided Design.
• We assume standard industry usage in engineering and architectural applications.

Concept / Approach:
CAD stands for Computer Aided Design. It refers to the use of computers and specialised software to assist in creating, modifying, analysing or optimising a design. CAD software allows engineers and designers to draw objects in two or three dimensions, check dimensions accurately and simulate how parts fit together. The word aided indicates that the computer assists the human designer, rather than replacing them entirely. Other phrases such as Common Aided Design or Communication Aided Design are not recognised technical expansions of CAD in this context. Therefore, Computer Aided Design is the correct full form.

Step-by-Step Solution:

Verification / Alternative check:
Engineering and architectural textbooks refer to CAD systems and explain that they stand for Computer Aided Design. They often discuss the advantages of CAD over manual drafting, such as ease of modification and higher precision. Course syllabi in mechanical and civil engineering list CAD alongside other computer aided technologies like CAM (Computer Aided Manufacturing). In all these sources, CAD is always expanded as Computer Aided Design, and no alternative expansions are given. This strong and consistent usage confirms that Computer Aided Design is the correct answer.

Why Other Options Are Wrong:

• Common Aided Design: Not a standard term in engineering or computer graphics.
• Complex Aided Design: Also not used in recognised technical contexts.
• Communication Aided Design: Could sound meaningful but is not the accepted expansion of CAD.
• Centralised Architecture Design: A phrase that may appear in other contexts but is not what CAD stands for.

Common Pitfalls:
Because the letter C can stand for many words, some learners guess expansions like Common or Complex, especially if they have not seen CAD in a design context. To avoid this, link CAD mentally with drafting and drawing, and remember that computers now aid designers in these tasks. Then the phrase Computer Aided Design should come to mind naturally. Once you fix this association, exam questions asking for the full form of CAD become easy marks.

Final Answer:
In design and drafting, CAD stands for Computer Aided Design.