Final answer:
To convert 321 feet to kilometers, you first convert feet to meters and then meters to kilometers, resulting in approximately 0.098 km, which is answer b.
Step-by-step explanation:
The new space launch system from NASA is 321 feet tall. To convert this to kilometers, we use the conversion factor that 1 meter equals 3.281 feet. First, we convert feet to meters: 321 feet / 3.281 feet/meter = 97.845 meters. Now, we convert meters to kilometers by dividing by 1,000: 97.845 meters / 1,000 = 0.097845 kilometers. When we round this to four significant figures, we get 0.09785 kilometers, which can be rounded further to 0.098 km (answer b).