The right answer is Sun Yat-sen.
There had been some influential intellectuals building a nationalist discourse even before the May Fourth Movement. But the radical and outspoken tone of the New Culture Movement achieved the grounds for a shift in minds via the intellectual work of the period and its politicization. A special emphasis is given on Sun Yat-sen’s political and intellectual contribution to the transition since he was not only a major political activist but also a theoretician whose works (Three Principles of People) have been influential on China’s nation-building process.