In PLC input wiring, what does sourcing vs sinking refer to, and why is correct matching essential?

• A. Sourcing means the input is driven by a high-side supply, and sinking means the input is returned to ground; selecting the correct type ensures a proper reference and prevents damage.
• B. Sourcing and sinking are just different names for shielded vs unshielded cables.
• C. Sourcing is for AC, sinking for DC;
• D. Sourcing means the PLC consumes current; sinking means the PLC supplies current.

Answer: (A)