What is the role of the stochastic error term ui in regression analysis?​

Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!

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answer; i believe that the correct answer is ( rivers);

by using  production possibilities graph.  opportunity costs are key expenses in financial matters and are utilized as a part of registering money saving advantage investigation of a venture. such expenses, be that as it may, are not recorded in the record books but rather are perceived in basic leadership by processing the money costs and their subsequent benefit or misfortune.