Which of the following has high tensile strength? A. Plain hot rolled wires B. Cold drawn wires C. Heat treated rolled wires D. All have same tensile strength

The correct answer is: C. Heat treated rolled wires.

Plain hot rolled wires are wires that have been rolled at high temperatures. This process makes them strong, but also makes them brittle. Cold drawn wires are wires that have been drawn through a die at room temperature. This process makes them stronger and more ductile than plain hot rolled wires. Heat treated rolled wires are wires that have been heat treated after being rolled. This process makes them even stronger and more ductile than cold drawn wires.

Here is a table that summarizes the properties of the three types of wires:

| Type of wire | Strength | Ductility |
| — | — | — |
| Plain hot rolled | Strong | Brittle |
| Cold drawn | Stronger | More ductile |
| Heat treated rolled | Strongest | Most ductile |

As you can see, heat treated rolled wires have the highest tensile strength and the most ductility.