An object that is projected straight downward with initial velocity v feet per second travels a distance s=vt+16t2, where t =time in seconds.If Ramón is standing on a balcony 84 feet above the ground and throws a penny straight down with an initial velocity of 10 feet per second, in how many seconds will it reach the ground?

• A. 6 seconds
• B. 3 seconds
• C. 8 seconds
• D. 2 seconds