The sentence is plural
Estamos is the only one that fits.
As the largest country in Central America with an area of 51,000 square miles (129,494 square kilometers), Nicaragua is about the size of New York State. The country is bounded by the Pacific Ocean and Caribbean Sea, with Honduras bordering it at the north and Costa Rica at the south. Nicaragua has three major geographic regions: the Pacific lowlands in the west, the Caribbean lowlands in the east, and the central highlands located between these two. Lake Managua and Lake Nicaragua are the country's largest lakes.The climate varies more from elevation than from the seasons. Rainfall fluctuates greatly in Nicaragua and is seasonal; the rainy period runs from May through October. The Caribbean lowlands are the wettest section of Central America, receiving between 98 and 256 inches (250 and 650 centimeters) of rain annually. The east receives heavy annual rainfall and can even see serious flooding during the rainy season, while the west is drier year-round.
