An engineer choose a cluster size of N=9 for a cellular network with the following specifications: -no sectoring -minimum SIR=18 dB -path loss exponent n=4 Choose the correct statement Select one: a. the cluster size should be 12 b. none of the statements is correct c. the chosen cluster size is not acceptable d. the chosen cluster size is the best based on system specifications e. the chosen cluster size is acceptable but can be further decreased f. the chosen cluster size is acceptable but should be further increased