.Masako buys a house in 1999. She obtains a mortgage that carries an annual internet rate of 12 per cent, and makes payment of $880 per month. The CPI in 100, in 2000 it is 110, and in 2001 it is 120. What is the inflation rate in 2001?

a.120 per cent

b.20 per cent

c.10 per cent

d.9 per cent