The keys of a safe with five locks are cloned and distributed among eight people such that any of five of eight people can open the safe. What is the least total number of keys?<spanclass=′latex−bold′>a)</span>18<spanclass=′latex−bold′>b)</span>20<spanclass=′latex−bold′>c)</span>22<spanclass=′latex−bold′>d)</span>24<spanclass=′latex−bold′>e)</span>25