If 2010 is the base year, then the inflation rate in 2015 equals a. [(CPI in 2015 - CPI in 2014) / CPI in 2010] x 100 b. [(CPI in 2015 - CPI in 2010) / CPI in 2010] x 100 c. [(CPI in 2015 - CPI in 2014) / CPI in 2014] x 100 d. [(CPI in 2015 - CPI in 2010) / CPI in 2014] x 100