Thermal conductivity of a metal is an important factor to consider in making quality weldments because:

Some metals, such as aluminum, have a high conductivity, which results in rapid heat dissipation and potential lack of fusion defects.

Some metals, such as stainless steel, have a low conductivity, which can lead to localized heat buildup and potential weld defects.

In some metals, such as aluminum, very high temperature gradients are produced, causing stresses during cooling.

None of the above.