Answer
Option C:
$$40=-16t^2+60t$$
Work Step by Step
The formula for the height in feet $s$, of an object launched vertically at 60 feet/sec after $t$ seconds is given as:
$s=-16t^2+60t$
To find the time when the object reaches 40ft, plug in $40$ for $s$:
$$40=-16t^2+60t$$
Which is option C