Table 5-6 Shows an Assistant Professor's Salary and the Respective

Table 5-6 shows an assistant professor's salary and the respective price indexes for the years 1967 and 1997. Use the table to answer questions .
Table 5-6

-Refer to Table 5-6. What has happened to an assistant professor's salary between 1967 and 1997?

A) Although the nominal salary increased 4-fold in the 30-year period, real salary increased by only 3.2 times.
B) The purchasing power of an assistant professor's salary has fallen by about 4.76%.
C) The purchasing power of an assistant professor's salary has increased by about 5.24%.
D) The real salary in 1997 is slightly higher than that in 1967.