For Years the Paul Ecke Ranch Had a Monopoly on Poinsettias.What

For years the Paul Ecke Ranch had a monopoly on poinsettias.What event was responsible for the end of this monopoly?

A) A university researcher discovered the special technique the Ecke Ranch used for growing poinsettias.After the researcher published the technique other firms were able to compete with the Ecke Ranch.
B) Other poinsettia sellers were finally able to take advantage of the network externalities that had given the Ecke Ranch its monopoly.
C) After 20 years,the patent the Ecke Ranch had been granted for its poinsettias expired.
D) The government took away the public franchise it had earlier given to the Ecke Ranch to be the sole legal provider of poinsettias.