Answer:
(a) Supplier
Explanation:
In database design, two tables are linked together using a FOREIGN KEY. A foreign key is formed from one or more columns of one table that reference or match another key (often called a primary key) in another table. In other words, when a column or a combination of columns on one table points to a primary key of another table, the column(s) will specify the foreign key.
<em>PS: A primary key is used to make each entry of a table unique. </em>
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In the given tables - Supplier, Product, Country - since the Supplier table has a column called <em>CountryId</em> referencing the CountryId column of the Country table, then <em>CountryId </em> is a <em>primary key</em> in Country table but a <em>foreign key</em> in Supplier table.
Therefore, the CREATE TABLE statement(s) of the Supplier table must specify a foreign key.