Answer:
B. 6,000
Step-by-step explanation:
First we need to convert km to m and we do this by multiplying 45 by 1000 because there are 1000 meters in a Kilometer (kilo means 1000). Then we divide 1000 by 15 and get 3,000. Then we multiply this by two because the trees are planted on both sides of the road. This leaves us with 6,000 trees planted all together.