Assume Nominal GDP Is $10,000 Trillion in Period 1 and $15,000

Assume nominal GDP is $10,000 trillion in period 1 and $15,000 trillion in period 2.If prices in period 2 are twice as high as in period 1,real GDP in period 2 is

A) $10,000 trillion measured in period 1 prices.
B) $12,500 trillion measured in period 1 prices.
C) $15,000 trillion measured in period 1 prices.
D) $7,500 trillion measured in period 1 prices.