Oxy-fuel hose type VD grade _____ is required.

The correct answer indicates that oxy-fuel hose type VD grade T is required for safe and effective use in thermite welding and other oxy-fuel applications. This specific grade is designed to withstand the high temperatures and pressures associated with oxy-fuel processes, ensuring durability and safety. Grade T hoses are typically made with materials that are resistant to flames and heat, which is essential in preventing combustion or degradation during use.

In addition, these hoses are often color-coded, with a specific marking that helps operators quickly identify the correct type of hose for their application. Proper selection of hose type is crucial for maintaining safety standards and ensuring efficient operation in welding practices.