This is an inference question and the right answer choice from this question is directly supported by the passage. Incorrect answer choices often states "could be true" answers.
The author explains how the attitude from the English in England started favoring towards Parliament instead of King with seventeenth century as the point of change.
Let's go to the answer choices.
A) Too strong. This might have been true and could have been true, but not supported by the passage explicitly.
B) This is probably the likely reason people started favoring Parliament instead of King, but this is not supported by the passage.
C) Considering the whole third paragraph and the flow of opinion by citizen moving towards Parliament, the power of English Kings is definitely weaker than that in eighteen century. (Correct)
D) We are only given growing authority in legal reform by Parliament. Frequency of the reform by Kings is not provided. Unsupported.
E) This is just nowhere to be found.