Which of the following describes ballast types as listed in maintenance material?

• A. Temporary and external
• B. Permanent and external
• C. Temporary and permanent
• D. External and permanent

Answer: (A)

Ballast types in maintenance materials are described by how long they’re used (temporary vs permanent) and where they’re placed relative to the structure (external vs internal). The option that fits this usual classification is temporary and external. Temporary indicates the ballast is only needed for a period during the work and will be removed afterward, while external means it’s placed outside the main structure rather than inside or integrated with it. This combination matches how maintenance scenarios typically describe ballast, as a short‑term measure used to stabilize equipment or loads without becoming a permanent part of the structure. The other pairings imply permanence or internal placement, which doesn’t align with the common maintenance material descriptions.