Question

which best describes what occurred during the détente era? arms reduction arms limitation alliance formation increased openness

Explanation:

The détente era was marked by efforts to limit arms between the U.S. and the Soviet - Union during the Cold - War. Arms reduction was part of this but not as prominent as arms limitation. Alliance formation was not the main characteristic, and increased openness was not the defining feature. Arms limitation agreements like SALT I and SALT II were key during détente.

Answer:

arms limitation