For 2022, the countries ranked by *nominal per capita income* from highest to lowest are:
1. (C) Russia
2. (A) China
3. (B) Brazil
4. (D) India
Therefore, the sequence is (C), (A), (B), (D). The correct option is (a).

In an economy, exclusion of _______ may lead to under estimation of the value of Gross Domestic Product (GDP).