The diagram below shows a shift in short-run aggregate supply from SRAS1\text{SRAS}_1SRAS1 to SRAS2\text{SRAS}_2SRAS2.
Which of the following is the most likely cause and short-run macroeconomic impact of this shift?
An increase in labour productivity, leading to a higher price level and lower real output.
A spike in the global price of imported raw materials, leading to a higher price level and lower real output.
A reduction in the rate of value-added tax (VAT), leading to a lower price level and higher real output.
An increase in the basic rate of income tax, leading to a lower price level and lower real output.