Answer:B - $80
Explanation: Producer surplus is the difference btw what a consumer is paying and what a producer is charging.
From the above questions, Tom tuned the following pianos:
Buyer willing to pay $155.
Tom tuned piano 1 for $120, therefore his surplus on piano 1 is $155 - $120 = $35
Tom tuned piano 2 for $125, therefore his surplus on piano 2 is $155 - $125 = $30
Tom tuned piano 3 for $140, therefore his surplus on piano 3 is $155 - $140 = $15
Tom tuned piano 4 for $160, therefore his surplus on piano 4 is $155 - $160 = ($5)
All together his surplus is $35+$30+$15 =$80