question:  What seems to be the invader's reason for visiting Earth?
context: INVADERS APPEAR IN BOSTON. NO COMMUNICATION FROM ANTARCTICA IN 6 HOURS STRANGE FORCE DEFLECTS PLANES FROM SAHARA AREA WORLD POLICE MOBILIZING The item below the last one said: Pacifica, June 7—The World Police are mobilizing, for the first time in fifty years. For the Invaders have spared no part of this planet in their depredations: they have laid Hong Kong waste; they have terrorized London; they have destroyed the lives of citizens in every member state and in every inhabited area. "The peoples of the world, then, know what they are, and know that we face the most momentous struggle in our history. "Since the Invaders first appeared in Wood River, Oregon, 24 hours ago, they have not once acknowledged our attempts to communicate, or in any way taken notice of our existence as reasoning beings. They have treated us precisely as we, in less enlightened days, might have treated a newly-discovered race of lower animals. They have examined us, dissected us, driven us mad, killed us with no discernable provocation; and this is more intolerable than any normal invasion. "I have no fear that the people of Earth will fail to meet this challenge, for there is no alternative. Not only our individual lives are threatened, but our existence as a race. Peter took it in fifteen seconds, running, and stumbled to a halt in front of the door marked "Radiation." It was a street scene in the Science City of Manhattan, flooded by the warm spring sunshine. There were left only two blood-red, malignant monstrosities somehow defiling the air they floated in; and below them, a pitiful huddle of flesh no longer recognizable as human beings. "The Invaders are here, citizens," the commentator was saying in a strangled voice. This isn't like a war, where the noncombatants' morale has to be kept up. There aren't going to be any noncombatants, this time. The Invaders were floating up the sloping side of a tall, pure white structure that dominated the rest.
output:  They are investigating humans in a scientific, albeit fatal, way.
options:  They recognize humans as intelligent beings and wanted to see what they have made.  They want to wage war with Earth and take it for themselves.  They are investigating humans in a scientific, albeit fatal, way.  They are investigating humans, making notes to not destroy their world indiscriminately.