Why was it difficult at times for American soldiers to know who was a Viet Cong (communist) and who was a South Vietnamese (non-communist)?

A) The Chinese gave the Viet Cong clothes to blend in

B) South Vietnamese would often wear communist uniforms on accident

C) Viet Cong disguised themselves as civilians

D) The Viet Cong stole
millions of uniforms and would pose as friendly soldiers