Under the National Education Policy 2020 the National Council of Educational Research and Training (NCERT) is the apex academic body for school education. It is entrusted with developing the National Curriculum Framework (NCF), the National Professional Standards for Teachers inputs and textbooks, and thereby setting academic standards and promoting quality in school education.

Since the question concerns promoting quality education and setting curricular standards, NCERT is the body that fits: the policy names it as the agency that prepares the NCF for school education and teacher education guidelines in consultation with stakeholders.

NAAC (printed here as National Accreditation and Assessment Council) only assesses and accredits higher education institutions after they are set up; it does not set education standards. There is no statutory body called the National Board of Education among the policy's regulators. AICTE is limited to technical education and, under the policy, is to be subsumed into the single higher education regulator.

National Council of Educational Research and Training (NCERT) option is correct.