Final answer:
Mount Saint Helens and Mt. Pinatubo are located in the Pacific Ring of Fire.
Step-by-step explanation:
The Pacific Ring of Fire is a region in the Pacific Ocean known for its intense volcanic and seismic activity. Among the given options, Mount Saint Helens and Mt. Pinatubo are located in the Pacific Ring of Fire. Therefore, the correct answer is d. III and IV.
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