Final Answer:
The state that has Mount Rainier National Park, Olympic National Park, and North Cascades National Park is Washington.
Step-by-step explanation:
Washington, located in the Pacific Northwest region of the United States, is home to several national parks, including Mount Rainier National Park, renowned for its iconic volcanic peak and diverse ecosystems. Olympic National Park, situated on the Olympic Peninsula, features a variety of landscapes, from lush rainforests to alpine peaks and rugged coastlines. North Cascades National Park, part of the Cascade Range, showcases dramatic mountain scenery, glaciers, and pristine wilderness. These parks collectively contribute to the natural beauty and ecological diversity of Washington, making it a popular destination for outdoor enthusiasts and nature lovers.