The statement that is true is:
Fidel Castro was a committed communist before he became leader of Cuba.
While Castro's government received substantial support from the Soviet Union after the Cuban Revolution in 1959, his political ideology and revolutionary activities were rooted in socialist and Marxist principles even before he officially came to power. Castro's alignment with communist ideology developed over time, especially as he consolidated power and moved away from earlier nationalist sentiments. The other statements misrepresent the historical context and Castro's beliefs.