Which of the following speeds is equivalent to 90 kilometers per hour? (1 kilometer = 1,000 meters) 

Choice A is correct. Since 1 kilometer is equal to 1,000 meters, it follows that 90 kilometers is equal to 90(1,000)=90,000  meters. Since 1 hour is equal to 60 minutes and 1 minute is equal to 60 seconds, it follows that 1 hour is equal to 60(60) = 3,600 seconds. Now is equal to \(\frac{90 \text { kilometers }}{1 \text { hour }} \text { is equal to } \frac{90,000 \text { meters }}{3,600 \text { seconds }}\), which reduces to \(\frac{25 \text { meters }}{1 \text { second }}\) or 25 meters per second. 
Choices B, C, and D are incorrect and may result from conceptual or calculation errors.