question: What is the purpose of the power headroom reports (PHR)? [3GPP Release 18] option 1: To provide support for power-aware packet scheduling option 2: To allocate resources for the initial HARQ transmissions to UEs option 3: To enable coordination of TDM and FDM cell resources between MAC in the gNB and the corresponding entity in the ng-eNB option 4: To enable fast SCell activation when CA is configured option 5: To provide support for QoS-aware packet scheduling 