If f(x) = 3x2, then F(x) =A. 6xB. x3C. x3 + CD. 6x + C

To solve the problem, we need to find the antiderivative (or indefinite integral) of the function $f(x) = 3x^2$.

Step 1: Identify the function to integrate. $f(x) = 3x^2$

Step 2: Use the power rule for integration, which states that the integral of $x^n$ is $\frac{x^{n+1}}{n+1}$, where $n \neq -1$.

Step 3: Apply the power rule to $3x^2$. $\int 3x^2 \, dx = 3 \int x^2 \, dx$

Step 4: Integrate $x^2$. $\int x^2 \, dx = \frac{x^{2+1}}{2+1} = \frac{x^3}{3}$

Step 5: Multiply by the constant 3. $3 \cdot \frac{x^3}{3} = x^3$

Step 6: Add the constant of integration $C$. $F(x) = x^3 + C$

Therefore, the correct answer is: $\text{C. } x^3 + C$