Suppose that you are constructing pylons. Pylons become increasingly costly to make as more pylons are constructed. That is: dC/dq = q2 where q is the number of pylons. Pylons benefit society according to the benefit function: B = 1.7q3-7.3q+c. As a welfare maximiser, you will build the number of pylons which benefit society. Suppose you have built 1 pylon. How many additional pylons must you construct?