Which of these is skeleton?

Skeleton is a winter sliding sport in which a person rides a small sled, known as a skeleton bobsled (or -sleigh), down a frozen track while lying face down and head-first. The sport and the sled may have been named from the bony appearance of the sled.

Unlike other sliding sports of bobsleigh and luge, the race always involves single riders. Like bobsleigh, but unlike luge, the race begins with a running start from the opening gate at the top of the course. The skeleton sled is thinner and heavier than the luge sled, and skeleton affords the rider more control, making it safer than luge. Skeleton is the slowest of the three sliding sports, as skeleton's face-down, head-first riding position is less aerodynamic than luge's face-up, feet-first ride.