Need help thanks I get 15 or 25 but I’m not sure if that’s right

Answer:
C
Step-by-step explanation:
From the graph we can see that after 2 hours she receives $40
Subtract the flat fee of $10 ← value on y- axis
She is paid $30 for 2 hours work, hence
hourly rate = [tex]\frac{30}{2}[/tex] = $15 → C