Final answer:
The rate of 56 miles per hour is expressed as a ratio of 56:1, indicating 56 miles for every 1 hour.
Step-by-step explanation:
The question asks to write the rate of 56 miles per hour as a ratio. A ratio is a comparison of two quantities showing the relative sizes of these quantities to each other. Since the rate is given as miles per hour, we want to express it using a colon to separate the terms of the ratio. The correct answer is 56:1, which means 56 miles for every 1 hour.