Machines using crawler chains are not allowed to cross public-roads of they posses.

Machines using crawler chains are not allowed to cross public roads if they possess Cleats or Grouser plates. Cleats or Grouser plates are metal protrusions that are mounted onto the crawler tracks of heavy machinery to provide better traction and stability on uneven surfaces. However, these plates can cause significant damage to public roads and are therefore not allowed for use on machines that need to cross public roads.

Option B, Smooth grouser plates, and Option C, Plain plates without rubber, do not have protrusions that can cause damage to public roads and are therefore allowed to be used on machines that need to cross public roads.

Therefore, the answer to this question is Option A, Cleats or Grouser plates.