What distinguishes an on-board processing (OBP) payload from a simple bent-pipe transponder?

• A. OBP decodes, routes, and regenerates data onboard; bent-pipe merely transfers uplink frequencies to downlink without payload processing.
• B. OBP uses only analog filtering; bent-pipe uses digital processing.
• C. OBP sends downlink frequencies identical to uplink; bent-pipe converts downlink.
• D. OBP is used only in GEO; bent-pipe only in LEO.

Answer: (B)