Concept:
The German sociologist Max Weber defined the modern state as an institution that successfully claims the monopoly of the legitimate use of physical force within a given territory.
According to Weber,
\[
\boxed{
\text{The State is a relation of men dominating men,}
}
\]
\[
\boxed{
\text{supported by means of legitimate violence.}
}
\]
This means that only the State possesses the legal authority to use coercive force for maintaining law and order.
Step 1: Examine the options.
• [(A)] Jeremy Jennings is a political theorist but not the author of this definition.
• [(B)] Andrew Heywood is known for political science textbooks.
• [(C)] Max Weber gave this famous definition of the State. Correct.
• [(D)] Karl Marx viewed the State as an instrument of class domination but did not define it in these terms.
Hence,
\[
\boxed{\text{Correct Answer}=(C)\;\text{Max Weber}}
\]