Answer:
The right answer is the Soviet Union and China.
Step-by-step explanation:
The USSR was the main provider of weapons and ammunition for the North Vietnamese army and the Viet Cong guerrillas in the South. The Vietnamese also got aid and assistance from the People´s Republic of China. This was an expression of Communist solidarity with comrades fighting a war of national liberation (from the Communist perspective) against American imperialism and its allies in South Vietnam.