Exam C2010-530 topic 1 question 11 discussion

A user is a member of four Non-Independent security groups which have different purchase order limits set for sites within the same organization.
Security Group 1 Site = Bedfont Purchase order limit = $1000
Security Group 2 Site = Bedfont, Southbank Purchase order limit = $15000
Security Group 3 Site = Portsmouth Purchase order limit = $20000
Security Group 4 Site = Farnham Purchase order limit = $3000
What will the purchase order limit be for the user when working with the Farnham site?