In a market research study, two samples were taken to estimate the proportion of consumers who prefer Brand A. The data are:
| Sample | Preference Rate | Margin of Error |
|---|---|---|
| C | 40% | 3.5% |
| D | 42% | 1.2% |
With identical sampling procedures and the same population, which best explains why Sample C's margin of error is larger than Sample D's?
Sample C had more nonresponses.
Sample C had a lower preference rate.
Sample C used a different survey instrument.
Sample C had a smaller sample size.
