I think there's a step I'm missing. Can someone guide me on how to solve? Many thanks. :)

Variable cells Final Valuel Cell Name $B$6 Activity 1 $C$6 Activity 2 $D$6 Activity 3 Constraints Reduced Cost 425 0.0 250 Objective Coefficient 500 300 400 Allowable Increase Allowable Decrease 1E+30 425 500 300 1E+30 250 27.5 0 Shadow Price 0 Cell $E$2 $E$3 $E$4 Name Benefit A Benefit B Benefit C Final Value 110 110 137.5 Constraint R.H. Side 60 110 80 Allowable Increase 50 1E+30 57.5 Allowable Decrease 1E+30 46 1E+30 75 If the coefficient for Activity 2 in the objective function changes to $400, then the objective function value: Multiple Choice O will increase by $7,500. will increase by $2,750. O will increase by $100. will remain the same