Exchange new ideas is the only answer that seems plausible
Answer:
D. An embargo on oil and weapons for all warring nations
Answer:
1940s and 50s when when the Veitnam was started

Studying and understanding the <u>c</u><u>u</u><u>l</u><u>t</u><u>u</u><u>r</u><u>e</u>, the <u>d</u><u>i</u><u>s</u><u>c</u><u>o</u><u>v</u><u>e</u><u>r</u><u>i</u><u>e</u><u>s</u>, the <u>e</u><u>x</u><u>p</u><u>e</u><u>r</u><u>i</u><u>e</u><u>n</u><u>c</u><u>e</u><u>s</u>, and the <u>a</u><u>r</u><u>t</u><u>i</u><u>f</u><u>a</u><u>c</u><u>t</u><u>s</u>, is people from the past will enable you to make good decisions for yourself and future generations.
hope it helps