To find the probability that a randomly selected student is in 9th grade and chose pizza, we need to use the following formula for probability:
\[ P(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]
From the data provided:
- The number of 9th graders who chose pizza is given as 30.
- The total number of students surveyed is 450.
Now, we can calculate the probability:
\[ P(\text{9th grade and pizza}) = \frac{30}{450} \]
To simplify this fraction:
\[ P(\text{9th grade and pizza}) = \frac{30 \div 30}{450 \div 30} = \frac{1}{15} \]
Now we can convert this to a percentage:
\[ P(\text{9th grade and pizza}) = \frac{1}{15} \times 100 \approx 6.67% \]
Therefore, the closest option to 6.67% is:
C. 7%