How do you know that berliners expected a retaliatory air strike following the attack on poland ?

They prepared a lightning war which is called Blitz Krieg. This was a plan on the situation since they have studied of the military actions as reactions of the countries that are helping each other, Germany, France and Poland. Germany had the military support of the USSR in agreement that Poland would be divided into two. 

Where are the choices?

In financial aspects, a depression is a sustained, long haul downturn in monetary movement in one or more economies. it is a more extreme monetary downturn than a recession, which is a slowdown in financial action through the span of a typical business cycle. a depression is an irregular and extreme type of recession. so depression is always followed by recession but it is not correct to state that a depression always follow a recession.