Answer:
B. A car sits at rest at a stop sign.
The toxic runoff from the farms will directly enters the water bodies of the earth through the drainage system.
The emissions from the cars will go into atmosphere and will react with water and then it will enter the earth's water. So, it is not directly affecting the earth's water.
The dumping trash on roadsides do not enter the earth's water. It can enter the earth's water through rains.
The production of oxygen by trees is not pollution.
Hence, option (A) is correct.
Here the block has two work done on it
1. Work done by gravity
2. Work done by friction force
So here it start from height "h" and then again raise to height hA after compressing the spring
So work done by the gravity is given as

Now work done by the friction force is to be calculated by finding total path length because friction force is a non conservative force and its work depends on total path


Total work done on it

So answer will be
None of these
Explanation:
If force or distance is increased, then amount of workdone will also increase.