Answer:
The correct answer is option B.
Step-by-step explanation:
Given speed of 72 km/hour.
1 kilometer = 1000 m
1 hour = 60 minutes
1 minutes = 60 seconds
1 hour = 60 × 60 seconds = 3600 seconds

= 20 m/s
72 km/h = 20 m/s
Hence, the correct answer is option B.