Assume that Costa, PLC buys a machine in 2003 for $200,000 when the general price index is 150. At the end of 2006, the index has risen to 210 and the current cost of the machine is $300,000. What would be the unrealized holding gain in general purchasing power terms?
a. $100,000
b. $220,000
c. $120,000
d. $80,000