Final answer:
Upon seeing a 'Maximum speed 60 km/h ahead' sign while driving, you should decrease your speed to comply with the new speed limit for safety and legal reasons.
Step-by-step explanation:
When you see a sign that reads, 'Maximum speed 60 km/h ahead,' as a responsible driver, you should: (d) Decrease speed and adhere to the indicated limit. This means that you should reduce your speed if necessary to ensure you are not going faster than 60 km/h when you enter the new speed zone. It is important to follow the designated speed limit to ensure safety for all road users and to comply with traffic laws.