premise: During a seven-year period, an amusement park builds exactly seven roller coasters—the Firecracker, the Gobbler, the Hurricane, the Jackrabbit, the Lasso, the Niagara, and the Pretzel. No two roller coasters are built in the same year. Each roller coaster is either steel or wooden. The following conditions must apply: The Pretzel is built in the second year. The roller coaster built in the first year is steel, and the one built in the seventh year is wooden. The Lasso is built after the Firecracker. The Jackrabbit and the Gobbler are built before the Hurricane. Exactly two of the roller coasters built after the Hurricane are steel. Wooden roller coasters are not built in any two consecutive years. Which one of the following roller coasters must be steel?
hypothesis: Firecracker