To determine the percentage of people who own fish based on the given survey data, follow these steps:
1. Identify the relative frequencies involved:
- Proportion of people who own both fish and birds: 0.04
- Proportion of people who own fish but not birds: 0.08
2. Calculate the total relative frequency of people who own fish:
[tex]\[
\text{Total relative frequency of fish owners} = \text{Proportion who own fish and birds} + \text{Proportion who own fish but not birds}
\][/tex]
Substituting the given values:
[tex]\[
\text{Total relative frequency of fish owners} = 0.04 + 0.08 = 0.12
\][/tex]
3. Convert the total relative frequency to a percentage:
[tex]\[
\text{Percentage of fish owners} = 0.12 \times 100 = 12.0\%
\][/tex]
Therefore, the percentage of people surveyed who own fish is [tex]\( 12\% \)[/tex].
The correct answer is D. [tex]\( 12\% \)[/tex].