Second order condition for profit maximisation of 3rd degree price discriminating monopoly is
1
MR1 = MR2 = MC
2
Slope of MR1 < Slope of MC Slope of MR2 < Slope of MC
3
Slope of MR1 = Slope of MR2 = Slope of MC
4
Slope of MR1 > Slope of MC
Slope of MR2 > Slope of MC