question: What is the new class of 6G services that requires joint uplink-downlink designs and can potentially offer energy to small devices via wireless energy transfer? option 1: Mobile Broadband Reliable Low Latency Communication (MBRLLC) option 2: Massive URLLC (mURLLC) option 3: Human-Centric Services (HCS) option 4: Multi-Purpose 3CLS and Energy Services (MPS) option 5: None of the above 