f(3.5) is asking what the f(x) is when x = 3.5
3.5 is right in between 3 and 4 so f(x) should be between 1.1 and 3.8
problem is there are B and C to choose from. I couldn't see a pattern in the data but when graphed in excel it appears to be a wide parabola with the equation:
y = 0.9768x² - 3.9561x +
4.0707
if you put in x = 3.5
y = 2.19
I don't know how your teacher expected you to choose between 2.11 and 2.19 though without being able to use more advanced tools to help you.