Final answer:
The most effective revision to make the language in the first sentence more precise would be option B: The Cuban Missile Crisis marked a turning point in the Cold War.
Step-by-step explanation:
The most effective revision to make the language in the first sentence more precise would be option B: The Cuban Missile Crisis marked a turning point in the Cold War. This revision accurately captures the significant impact of the crisis on the Cold War and conveys the idea that it was a pivotal moment in the conflict between the superpowers.