Answer:
A) It encourages unity between nations.
Step-by-step explanation:
The quote: "Let both sides explore what problems unite us instead of belaboring those problems which divide us." speaks of unity between former Soviet Union and the States.
The repetition of the word both suggests both countries, facing similar issues, should come together to a shared solution.
Another quote that speaks of unity: "Together let us explore the stars, conquer the deserts, eradicate disease, tap the ocean depths, and encourage the arts and commerce."