The gate at the entrance of a Shinto shrine is called a torii.
A torii is a traditional Japanese gateway that marks the transition from ordinary space into an area associated with kami, or Shinto deities. Shrine approaches, called sandō, commonly pass beneath one or more torii before reaching the worship buildings. A torii therefore functions as a boundary marker rather than as a sealed entrance: visitors can usually walk through freely.
Some shrines have several torii arranged along the approach. The outermost gate may be distinguished from later gates closer to the sanctuary, where the perceived sacredness increases. Torii vary widely in design, including simple wooden forms, stone structures, and the bright vermilion gates associated with many shrines.
The other choices refer to different shrine objects or buildings. The honden is the main sanctuary where the kami is enshrined; komainu are guardian statues; and a tōrō is a lantern. Torii are strongly associated with Shinto, although historical examples also appeared in Buddhist settings, so the gate itself is not an absolute religious dividing line.