Haidilao is a popular hotpot chain in Singapore. The restaurant is famous for its good quality food and superb services. During peak hours, crowds of customers need to sit outside the store, waiting for their queue numbers to be called. The waiting time can be as long as two hours. (a) (b) Evaluate the two (2) types of variability arising in the service processes of this restaurant. Give some examples for each type of variability. Which variability plays the major role? What kind of variability is introduced by the outbreak of Covid-19? (15 marks) In the OM triangle, which strategy is the best one to deal with the above- mentioned variability(ies)? Why are the other two (2) strategies not optimal? (10 marks)