The answer would be B. By giving the soil time to rest, nutrients are able to be restored.
Answer:
1. Poland was not prepared for war and the rate at which Germany had swept across its nation.
2. U-Boats were valuable assets of the German Kriegsmarine during WWII. They were used to sink naval ships and to interfere with allied trade routes and supply lines, with great affect.
3. The Luftwaffe was Germany's air force during WWII, and played a great role during the Battle of Britain. It was used to wreak havoc through the use of air raids, or blitzkrieg (translates to "lightning war").
Basic problem!
So every week he receives $7. This is then added to his total every week. So in 4 weeks, this means he has added 7+7+7+7, also known as 7x4. This results in an answer of $28 after 4 weeks!