A bird is flying at a constant rate. This equation y = 8x + 15 can be used to represent this situation, where y is the bird's elevation in meters and x is the number of minutes the bird has been flying.

Which statement best describes the bird's elevation, given this equation?

The bird started at a height of 15 meters and is ascending at 8 meters per minute.

The bird started at a height of 8 meters and is ascending at 15 meters per minute.

The bird started at a height of 15 meters and is descending at 8 meters per minute.

The bird started at a height of 8 meters and is descending at 15 meters per minute.