The correct answer is - C.) eliminating barriers to trade benefits the economies of member nations.
The regional trade blocs, in fact all trade blocks, are very useful for the economies of the countries that are members in the trade block. The benefit can be seen in the economic sector, as the countries can both, export products on larger markets without tariffs, and import products without imposing tariffs, which benefits the consumers as the prices are lower in that way.
The trade blocks have become a common thing in the world during the 20th century, and that has helped the economies of lot of countries, as well as the choices available and buying power of the consumers.
Since scarcity is when the supply of a product goes low
the price goes up when the supply of a product is down
A majority of canada's population live in lake ontario
Liquid water cannot persist at the moon's surface, and water vapor is decomposed by sunlight, with hydrogen quickly lost to outer space. However, scientists have since the 1960s conjectured that water ice could survive in cold, permanently shadowed craters at the Moon's poles.
hope I helped :-)