A ball is thrown straight up with an initial velocity of $128$ ft$/$sec$,$ so that its height $($in feet$)$ after$$x$$seconds is given by h$($x$)=128$x $-16$x$^2.$

Sally computes the slope of the tangent at x $=8$ seconds and finds h$(8)=-128$ ft$/$sec$.$What does Sally's computation tell you about the velocity of the ball at exactly $8$ seconds into flight?

Group of answer choices

The ball is traveling downward at a speed of $8$ ft$/$sec at x $=128$ seconds.

The ball is traveling upward at a speed of $128$ ft$/$sec at x $=8$ seconds.

The ball is traveling downward at a speed of $128$ ft$/$sec when it hits the ground.

The ball is traveling downward at a speed of $8$ ft$/$sec when it hits the ground.