Answer:
B. Countries receiving economic assistance from the US.
Step-by-step explanation:
The Marshall Plan was a US government plan with the objective of providing aid to the countries affected by the Second World War. This plan was also known as the European Recovery Program, enacted in 1948.
The given poster is from one of the entries from the Intra-European Cooperation for a Better Standard of Living Poster Contest held all over Europe in 1950. This poster contains the flags of countries that receive aid under the plan namely, Portugal, Norway, Belgium, Iceland, West Germany, the Free Territory of Trieste, Italy, Denmark, Austria, the Netherlands, Ireland, Sweden, Turkey, Greece, France, and the United Kingdom.
Thus, the correct answer is option B.