What does a sinking input or output do?

• A. A sinking input provides a path to supply voltage.
• B. A sinking input provides a path to ground for the load.
• C. The sinking input is used for clock synchronization.
• D. A sinking output provides current to ground.

Answer: (C)

Sinking means current is directed toward ground. When an input is sinking, activating it completes a path to ground, so the device sees a grounded reference. When an output is sinking, it ties the load to ground, allowing current to flow from the supply, through the load, and into ground.

So the essential idea is that sinking I/O provides a path to ground for current rather than pushing current up to the supply. The option describing a path to ground captures this behavior. Offering a path to supply voltage describes sourcing, and clock synchronization is not a defining role of sinking I/O. The statement about a sinking output delivering current to ground is true for that specific case, but the broader concept is about grounding the current path.