Repair or replace unsatisfactory markings immediately and at no additional cost to the department, if the marking were in place for __________ days or less.

The correct response is based on standard practices related to the maintenance of traffic markings. When markings are installed and found to be unsatisfactory within a specific time frame, the guidelines dictate that they must be repaired or replaced immediately and at no additional cost. This requirement is crucial to ensure safety and compliance with traffic regulations. In this case, unsatisfactory markings must be addressed within 120 calendar days.

Addressing the time frame of 120 calendar days reflects a common industry standard where a reasonable period allows for identifying issues with new markings, while still holding contractors accountable for quality and safety. This time frame helps ensure that any deficiencies are corrected promptly, minimizing risk to drivers and maintaining the integrity of the roadway.

The other options present shorter time frames, which may not align with industry practices or provide sufficient time for evaluation after marking installation. Adhering to a longer period ensures that contractors take responsibility for the quality of their work while also allowing for appropriate administrative oversight.