Paints and finishes — varnish is defined as a transparent or semi-transparent protective coating consisting of resinous substances dissolved or carried in which of the following media?

Introduction / Context:
In building materials and architectural finishes, varnish is a clear or lightly tinted coating used to protect and enhance the appearance of wood, metals, and some masonry surfaces. Understanding what a varnish is made of (resins plus an appropriate vehicle/solvent or oil) helps you choose the right product for durability, drying time, and visual effect.

Given Data / Assumptions:

• The question asks which media can serve in a varnish system for dissolving or carrying resinous substances.
• Traditional and modern varnishes include spirit varnishes, oil varnishes, and turpentine/solvent-borne types.
• Terminology in civil engineering exams often groups vehicles (drying oils) and solvents as acceptable carriers for resins.

Concept / Approach:

Varnish fundamentally contains a resin (natural or synthetic) plus a vehicle (drying oil and/or solvent) that enables application and forms a film after drying/curing. Spirit varnishes dissolve resins in alcohol (e.g., shellac). Oil varnishes dissolve resins in a drying oil such as linseed oil, sometimes with additional solvent for brushability. Turpentine and similar hydrocarbons act as solvents that thin and carry resins or resin-oil blends, evaporating after application.

Step-by-Step Solution:

Verification / Alternative check:

Traditional finishing manuals classify varnishes into spirit (alcohol-based), oil (linseed/tung based), and resin-solvent blends (often reduced with turpentine or mineral spirits), confirming the breadth of acceptable media.

Why Other Options Are Wrong:

Choosing only one of alcohol, linseed, or turpentine would exclude other standard varnish types; the correct holistic choice is all the above.

Common Pitfalls:

Confusing varnishes with paints (which contain pigments) or with lacquers (thermoplastic resins re-dissolvable in solvents). Also, forgetting that linseed acts as a vehicle (binder) rather than a mere solvent.

Final Answer:

all the above