125% maybe i don’t know for sure
        
             
        
        
        
You're pretty close. It's all in the details.
A. Correct.
B. Correct.
C. Sign error in the boxed answer. -(-0.5) = 0.5
The graph shows c ≈ 1.855. If a is more than that and decreasing, area is increasing. The sign of dA/dt will be positive. (Compare to D)
D. Units are not shown. Numerical value is correct.
 
        
        
        
Cylinder is 10 meters wide, so its diameter is 10 meters. You get radius of it by dividing 10 by 2, which equals 5.
As you count volume of cylinder from that equation
 
 You get an equation to count height:
 
 h≈3.82 meters