Is it easier for a central bank to be independent in a high-income country or in a low-income country?

a- It is often difficult for a central bank to act independently in a low-income country.

b- It is often difficult for a central bank to act independently in a high-income country.

c- Low-income countries rarely have central banks.

d- The independence of a central bank does not depend on the level of a country's income.