A projectile's height , in meters, above the ground seconds after launch is modeled by the equation , where is the initial upward velocity in meters per second, and is the initial height in meters. For a specific launch, the equation is . Which statement best describes the meaning of the term "15t" in this equation?
The initial height of the projectile.
The height of the projectile after 15 seconds.
The contribution to the projectile's height due to its initial upward velocity.
The maximum height reached by the projectile.
