To find the ratio of episodes with Gary to episodes with Elena, we need to write it as a fraction and simplify it:
The ratio is:
\[ \text{Ratio} = \frac{\text{Episodes with Gary}}{\text{Episodes with Elena}} = \frac{325}{525} \]
Now we can simplify this fraction. We can find the greatest common divisor (GCD) of 325 and 525 first.
The prime factorizations are:
- \( 325 = 5^2 \times 13 \)
- \( 525 = 5^2 \times 21 = 5^2 \times 3 \times 7 \)
The common factor is \( 5^2 \), so the GCD is 25.
Now, we can simplify:
\[ \frac{325 \div 25}{525 \div 25} = \frac{13}{21} \]
Thus, the simplified ratio of episodes with Gary to episodes with Elena is:
\[ \text{Ratio} = 13 : 21 \]
So the correct answer is D. 13 to 21.