Use the Following to Answer Questions -Tony Has a Cell Phone,and His Service Provider Is Rogers

Use the following to answer questions : $$\begin{array}{l}\text { Table: Externalities from Parks }\\\begin{array} { c c c } \hline \begin{array} { l } \text { Quantity of } \\\text { Land (acres) }\end{array} & \begin{array} { c } \text { Marginal } \\\text { Social } \\\text { Benefit }\end{array} & \begin{array} { c } \text { Marginal } \\\text { Social } \\\text { Cost }\end{array} \\\hline 0 & \$ 225 & \$ 0 \\1 & 200 & 50 \\3 & 150 & 150 \\4 & 125 & 200 \\5 & 100 & 250 \\9 & 0 & 450 \\\hline\end{array}\end{array}$$
-Tony has a cell phone,and his service provider is Rogers.When he calls his wife,Meleah,who is also a Rogers customer,he does not have to pay for those minutes.The more Rogers customers there are in the market,the more benefit Tony receives.This is:

A) a network externality.
B) the Coase theorem.
C) a Pigouvian subsidy.
D) a technology spillover.