Read the following news and answer the following questions.

Bank of Japan inches back presence in bond market (Source: Nikkei Asian Review; 21/03/2019)

The proportion of government bonds held by the Bank of Japan fell for the first time in six years and nine months as the central bank gradually curbs its massive monetary easing program.

At the end of December, the BOJ held 42.99% of all issued Japanese government bonds, according to its own data, or 478 trillion yen ($4.29 trillion) of 1.11 quadrillion yen in outstanding debt, down slightly from 43% at the end of September.

a. Why does the Bank of Japan not use the traditional monetary policy to achieve its policy objectives? Explain

b. What are the major differences between the Bank of Japan's quantitative easing policy and the traditional monetary policy? Explain.

c. What are the costs of deflation to Japanese Economy?