Question

In each of the following situations, identify if there is a positive or negative externality in play. Explain you answer thoroughly.
A local bridal shop shares a strip mall with eight other businesses. Recently all have agreed that the signage at the road needs a facelift. Although all eight businesses use the sign, the other seven are not willing to pay for a fresh paint job. The bridal shop decides to foot the bill and, on their own, they update the sign. Is there a positive or negative externality in play? Why?