I do not quite get what the difference between relevant and irrelevant cost is, can you explain with these questions?

Do 3) Label each item below as relevant or irrelevant in making a decision. (4 marks) Cost of insurance on a new vehicle when evaluating purchase of new vehicle Cost of roof repair made on rental property last year when evaluating sale of rental property Original cost of old equipment that is being evaluated for replacement Cost of new equipment that is under evaluation to replace used equipment Accumulated depreciation on old equipment being evaluated for replacement F. Cost of previous year's insurance policy on old equipment being evaluated for replacement Answer: A B C D E F