Final answer:
The most widespread method of weld inspection is visual testing, which allows for the direct observation of weld defects without specialized equipment.
Step-by-step explanation:
The most widespread method of weld inspection is B) Visual testing. This method involves the inspector looking at the welds directly to identify any obvious defects such as cracks, pits, or incorrect weld profiles. Compared to the other methods listed, visual testing is the most basic and accessible form of inspection used in both industrial and non-industrial settings due to its simplicity and cost-effectiveness.
While other testing methods like ultrasound, which is greatly beneficial for its nondestructive attributes, can reveal cracks and voids in solids that are too small for x-rays and measure the thickness of coatings with precision, visual inspection remains the most widespread due to its immediate applicability without the need for specialized equipment.