The correct answer is D. CBDT.
The CBDT is the Central Board of Direct Taxes, a department of the Government of India that is responsible for the administration of direct taxes in India. It is not an international organization.
SAARC is the South Asian Association for Regional Cooperation, a regional intergovernmental organization that promotes economic, social, cultural, technical, and scientific cooperation among its member states.
ASEM is the Asia-Europe Meeting, a forum for dialogue and cooperation between Asia and Europe.
ASEAN is the Association of Southeast Asian Nations, a regional intergovernmental organization that promotes economic, social, cultural, technical, and scientific cooperation among its member states.