'Broadcasting one's ambition' suggests that a person is openly sharing their career goals, which is a characteristic of a direct and high-profile approach to resignation. Option A is incorrect because 'broadcasting' implies the opposite of keeping secrets. Option C is incorrect because it suggests uncertainty, which is not consistent with broadcasting ambition. Option D is incorrect because it introduces external pressure, which is not the focus of the phrase. The correct answer is B, as it aligns with the concept of openly sharing career ambitions.