How was the german military strategy blitzkrieg important during world war ii?

The blitzkrieg or "Lightning War" was a German tactic, the use of a combination of mobile forces of aviation, artillery, tanks and infantry, mainly, which created a complete disorganization among hostile forces. Successful execution of this tactic leads to short military actions that saves people's lives and limits the expenditure of artillery. The implementation of this tactic enabled the successful conquest of Belgium, the Netherlands and France in Europe, and also used Rommel during a campaign in North Africa.

c is the correct answer for this question.

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.