Assume integer quantities. The table below shows the demand schedule faced by a monopoly firm, that faces a constant marginal cost of production of $43. The production of the good creates a marginal external cost equal to $9. Q 2 3 4 5 6 7 MWTP $83 $79 $71 $67 $55 $32 $25 If the firm engaged in perfect first-degree price discrimination, total surplus equals $