Final answer:
The correct answer is Option 3. Tire pressure gauges cannot be visually determined if they are accurate. The accuracy of a tire pressure gauge can only be determined by comparing it to a known accurate gauge.
Step-by-step explanation:
Tire pressure gauges are not accurate by visual inspection alone. To determine the accuracy of a tire pressure gauge, it needs to be compared to a known accurate gauge. By comparing the reading of the gauge in question to a known accurate gauge, you can determine if the gauge is accurate or not.