Filing of accounts

In order to answer the following question, do I have to learn or memorize the requirements of these different options. I think both option a) and option c) are correct. Since the question does not ask for, like, in country A or country B, I think, therefore both option b) and d) are incorrect. The question seems to be asking generally and not with respect to a particular country.

Question: The preparation and filing of accounts by limited companies each year is required by which of the following?
a) Codes of corporate governance
b) National legislation
c) International accounting standards
d) local accounting standards