A trebuchet launches a projectile from a hilltop 30 feet above ground level on a parabolic arc at a velocity of 40 feet per second. The equation h=−16t2+40t+30 models the projectile's h height at t seconds. How long will it take for the projectile to hit its target on the ground (to the nearest tenth of a second)?

2.8 seconds

3.1 seconds

3.5 seconds

3.9 seconds