None of your answers above will answer the question. The proper value for x = 1/2 is 7/4. The work for this is below.
f(x) = 3x^2 + 1
f(1/2) = 3(1/2)^2 + 1
f(1/2) = 3(1/4) + 1
f(1/2) = 3/4 + 1
f(1/2) = 7/4
I assume you may have missed something in typing, but 7/4 would be your answer.