A gaming platform company collected data on the difficulty level chosen by different players on their platform . There are three difficulty levels - Beginner , Regular and Expert( listed in the order of increasing difficulty). The company would like to know how customer age influences the effect of gaming experience ( number of weeks playing the game ) on the difficulty level chosen. Specifically , the following variables are available:

Age : customer age

Exp: number of weeks playing the game

Difficulty : Difficulty level chosen , 1 = Beginners , 2 = Regular, 3= Expert

(a) carefully describe the utility model for an" ordered multinomial logit model " for understanding how the effect of gaming experience on gaming difficulty level depends on customer age .

(b)carefully describe the utility model for an " unordered multinomial logit model " for understanding how the effect of gaming experience on gaming difficulty level depends on customer age .