 Of the following options, which seems to be Tremaine's biggest asset in his investigation?
In his room at the Elsby Commercial Hotel, Tremaine opened his luggage and took out a small tool kit, used a screwdriver to remove the bottom cover plate from the telephone. He inserted a tiny aluminum cylinder, crimped wires and replaced the cover. Meantime, I'm not sitting in this damned room crouched over a dial. You elected me to be a leg-man: now let me do it my way." And since it seems to be pinpointed in your home area—" "You don't have to justify yourself. Now I want answers, not questions! I'm warning you, Tremaine. Tremaine left the hotel, walked two blocks west along Commerce Street and turned in at a yellow brick building with the words ELSBY MUNICIPAL POLICE cut in the stone lintel above the door. "Jimmy," he said, "Jimmy Tremaine." In a back room Tremaine said, "To everybody but you this is just a visit to the old home town. Tremaine covered the discovery of the powerful unidentified interference on the high-security hyperwave band, the discovery that each transmission produced not one but a pattern of "fixes" on the point of origin. It showed a set of concentric circles, overlapped by a similar group of rings. "I think what we're getting is an echo effect from each of these points of intersection. The rings themselves represent the diffraction pattern—" "Hold it, Jimmy. "The point is this, Jess: we think we've got it narrowed down to this section. "Course," said Jess, "there's always Mr. Bram ..." "Mr. Bram," repeated Tremaine. "I've never seen any harm in Bram," said Jess. Tremaine stubbed out his cigarette, lit another. They used to raise cain in the other drug store...." I used to think she was some kind of princess...." Miss Linda was maybe in her twenties—and that made her an old maid, in those times. "After dark. II Back in the street, Tremaine headed south toward the Elsby Town Hall, a squat structure of brownish-red brick, crouched under yellow autumn trees at the end of Sheridan Street. Tremaine went up the steps and past heavy double doors. Ten yards along the dim corridor, a hand-lettered cardboard sign over a black-varnished door said "MUNICIPAL OFFICE OF RECORD." A thin man with garters above the elbow looked over his shoulder at Tremaine.
 His history with the town. Folks knew him and were more willing to help him like Miss Carroll, and he knew how to motivate people, like he did by bribing the record keeper for help.
 His history with the town. Folks knew him and were more willing to help him like Miss Carroll, and he knew how to motivate people, like he did by bribing the record keeper for help.  His good looks. They help him flirt with women like Miss Carroll and the librarian, so he could get more information.  His strength. He was able to bust down the door at Mr. Bram's home and catch him in the act of transmitting data.  His ruthlessness. He was strict enough to draw boundaries with the state police that helped his investigation significantly.