$16.$ Three students $-$ Michael, Alia, and Matthew are standing on a roof that is $6\mathrm{.}0$ meters high.$$ Each person throws a ball with the velocity as illustrated.$$ Assuming that air resistance may be ignored, whose ball will have the greatest speed the instant before they hit the ground? $$

a$)$ Kayla$$s$$ d$)$ Kayla$$s and Trevor$$s balls will have the greatest speed.$$

b$)$ Kristin$$s$$ e$)$ All three balls will have the same speed.$$

c$)$ Trevor$$s