Part b says producing zlurp creates pollution each bottle

Question

Willingness to pay:

first bottle-$5

second bottle-$4

third bottle-$3

fourth bottle-$2

fifth bottle-$1

part A asks how many each person will consume and for consumer surplus if the cost of each bottle is 1.50. The answer is four bottles with a consumer surplus of $8.

part B says "producing Zlurp creates pollution. Each bottle has an external cost of $1. Taking this additional cost into account, what is the total surplus per person in the allocation described in part A?"