Answer:
Condemnation
Step-by-step explanation:
The school board would institute condemnation if they attempt to follow it up. Condemnation can be defined as seizing people's private properties by the government for the public to use. Such an owner must be compensated though.
From the question since William has refused to sell due to price differences, this principal could take the case to court after all the property was to be used for public use and the court would institute condemnation.