there are four resources and four jobs to be done. assume there must be one-to-one matching between jobs and resources. the time required for each resource to do each job is as follows: job (hours) resource a b c d 1 5 8 7 7 2 4 9 5 9 3 6 9 8 7 4 7 6 6 9 for the optimal schedule, what is the total number of hours required to complete these jobs? multiple choice 22 hours 19 hours 21 hours 23 hours 20 hours