What did the ussr and the usa need to do to prevent conflictbetween the two superpowers?

UUSR and USA should have given up the Arms race and assured each other to end the conflict.

Explanation:

What eventually happened between the US and USSr in the time of late 1980s was a mutual agreement to disarm the two countries of nuclear warheads or at least strip them of their numbers considerably and to generate less animosity.

This was done on the basis of dialogue between the two leaders of the countries and thus it was possible to achieve this even before with simple diplomacy and assurance that there will  be no escalation of conflict.

the answer is b. osage.