Answer:
A). Forced the Soviets to spend extensively to keep pace.
Step-by-step explanation:
The United States' 40th president Ronald Reagan proposed one of his massive and influential project 'Strategic Defense Initiative.' It was basically a missile defense system that aimed to safeguard the United States from any kind of underwater ballistic attack and nuclear attacks. It was so effective that 'it forced the Soviets to spend extensively to keep pace' with Reagan's excellent anti-ballistic missile program. It also pressurized USST to develop a system that was similar to his. Thus, option A is the correct answer.