What can you learn from attribution reports?

What can you learn from attribution reports? 

A) Budget usage for all Search campaigns, including limitations and opportunities for more traffic
B) The series of steps customers take after completing a conversion, including information on ads, clicks and elements of a campaign 
C) The series of steps customer take before completing a conversion, including information on ads, clicks and elements of a campaign
D) The number of conversions the same customer completes after clicking an ad