Shares a border with mexico a. guatemala b. costa rica c. puerto rico d. honduras

The correct answer is - A. Guatemala.

Mexico is the third largest country in North America, and it has land borders with three countries, one of which is Guatemala, and the other two being the United States (on the north) and Belize (on the southeast). Guatemala shares a border with Mexico on its northern and western side, while from Mexico's perspective, the border with Guatemala is on the southeastern part of the country. The region when the border between the two countries is, is a region covered with dense tropical rainforest.

81 is a composite number.