The total number of balls in the box is: \[ 3 \text{ (blue)} + 2 \text{ (white)} + 4 \text{ (red)} = 9 \text{ balls} \] The number of balls that are not white is: \[ 3 \text{ (blue)} + 4 \text{ (red)} = 7 \text{ balls} \] Thus, the probability that a ball drawn at random is not white is: \[ P(\text{not white}) = \frac{\text{Number of non-white balls}}{\text{Total number of balls}} = \frac{7}{9} \]
The correct option is (C): \(\frac{7}{9}\)