For the values given in the Table, a regret matrix is created. Because the objective is
minimization, the minimum value of each event is selected. The smallest value of each event is subtracted from all other values in relevant column. Thus, a regret matrix is created. This table shows the regret matrix of the problem.

According to the results in Table, maximum regret of each alternatives are as follows:
Product 1 = maximum regret = 5 days
Product 2 = maximum regret = 8 days
Product 3 = maximum regret = 6 days
Product 4 = maximum regret = 4 days
Product 5 = maximum regret = 3 days
The alternative with the smallest value (product 5) is chosen among the maximum regrets. The correct answer is E.