Economic growth takes place when a country

An economic growth means that a country produces and consumes more than in the past - this is the correct answer. This means that a poorer country can have a higher economic growth than a richer one - since it's only compared to its economic activity before, and not to the economic activity of the other countries.

I believe the answer is: measures its gross domestic product (GDP).

Gross domestic product accounted for all valued goods or services that the nation managed to produce on a single year.

A country is considered to be experiencing economic product if the gross domestic product for the current year is bigger compared to the gross domestic product from last year