question:  What is Eddie's response to Teena's mother's concern over the missing isotope?
context: “You may use the Geiger counter any time you want, Eddie,” Mr. Taylor said, “as long as you take good care of it. Still, one clue is as good as another when it comes to hunting uranium ore, I guess. It could start cavities. Get at it right away, and you’ll still have time to hunt your uranium. In fact, anything having to do with atomic science excited him. You couldn’t have a father who was head of the atomic-science department at Oceanview College without picking up a little knowledge along the way. When carefully controlled, the radiation stored up in such isotopes was used in many beneficial ways. One reason for asking that particular question was to keep from prying deeper into the subject of the radioisotope. His father usually volunteered any information he wanted known, so Eddie stuck to questions which could and would be answered. At the speed atomic science is moving today, we simply can’t afford to waste time. It took Eddie over an hour to sort out the newspapers and magazines in the garage, tie them in neat bundles, and place them out on the front curb for the Goodwill pickup. “Anything else, Mom?” he asked, returning to the house and getting the Geiger counter out of the closet. Besides, there were plenty of other places around the outskirts of Oceanview where likely looking rock formations invited search with a Geiger counter. 20 Eddie went inside and followed Teena to the kitchen. They had been ever since Eddie’s family had moved to Oceanview and his father had become head of the college’s atomic-science department. Teena’s father was chief engineer for the Acme Aviation Company, one of the coast town’s largest manufacturing concerns. Teena’s mother glanced at the Geiger counter which Eddie had set carefully on the dinette table. 22 “Oh, yes, it’s fun, Mother,” Teena replied, wrapping wax paper around a sandwich. “Don’t go too far out from town,” Mrs. Ross cautioned, as Eddie picked up the Geiger counter.
output:  He tries to comfort her by explaining isotopes.
options:  He only causes more concern for her after explaining isotopes.  He acts equally as concerned as her.  He tries to comfort her by explaining isotopes.  He tries to demonstrate his knowledge of radioactivity to her.