Answer:
The correct answer is D: quadrilateral
.
Explanation:
Quadrilateral refers to any figure, concept, or thing that has four parts.
So, as the agreement was made between four countries, it should be called the Quadrilateral Agreement.
The Quadrilateral Agreement can be considered as an Agreement signed by four counties.
Trilateral refers to any figure, concept, or thing that has three parts, while the prefix bi- refers to any figure, concept, or thing that has two parts, so these cannot be considered as the correct answers.
