Read the excerpt below from Steve Jobs: The Man Who Thought Different and answer the question.

Before the adoption could be finalized, however, she learned that neither parent had a college degree. She balked and only agreed to complete the adoption a few months later, “when my parents promised that I would go to college,” said Jobs.
What is the meaning of the word "balked" as it is used in the excerpt?

accepted
protested
squawked
encouraged