Please help with the question below, many thanks !

Question 1 1 pts An environmental agency worker has the responsibility of estimating the mean carbon content of a particular day's steel output at a local steel factory. She uses a random sample of 15 rods from that day's output. The actual population distribution of carbon content is not known to be normal, but graphical displays such as a Q-Q plot indicate that the assumption of normality is not unreasonable. The testing process is newly developed so there is not historical data on the variability of the process. In estimating this day's mean carbon content, the primary reason that the worker should use a t-confidence interval rather than a z- confidence interval is because the worker... O is estimating the population mean using the sample mean. O is using the sample variance as an estimate for the population variance. O has a small sample, and a z-confidence interval should never be used with a small sample. O is using data from a specific day only