All of the following are considered possible general sources of shocks that can cause business cycles, except: (a) flexible prices (b) irregular innovation (c) productivity changes (d) monetary factors

The correct answer is a: flexible price.

Flexible price refers to the negotiable price of a good or service. Flexible prices are standard when pricing a commodity or service based on the flexible pricing strategy. Under a flexible pricing strategy, a product's final cost is negotiable between the seller and buyer.

Irregular innovation is a source of shock in the business cycle because it leads to an increase in productivity, leading to a rise in the economic GDP. Productivity changes are also considered a source of shock in the business cycle because it directly affects the GDP. Lastly, monetary factors are the other sources of business cycle shocks. Monetary policies impact investment in a country, which directly impacts the economic output. Flexible prices don't directly affect the GDP, and thus it is not a business cycle shock source since it cannot cause upwards and downwards economic output movement.