Explanation:

- In the sentence, "He was, in the early part of the twentieth century, a staunch nationalist of the liberal fold," the word "liberal" indicates openness to new ideas and a willingness to accept different opinions.

- Option 1: profuse - means abundant or in large quantities, unrelated to open-mindedness.

- Option 2: dogmatic - means asserting opinions in an authoritative manner, contrary to being liberal.

- Option 3: plentiful - means in large supply, not connected to openness or tolerance.

- Option 4: tolerant - means accepting of different views and willing to consider new ideas, closely related to "liberal." Correct Answer