A random sample of $40$ observations from a normally distributed population is drawn, and used to obtain a $90$% confidence interval for the population mean. Which one of the following statements is TRUE?
A. $90$% of all such calculated intervals will contain the true population mean.
B. $90$% of the population values are within this interval.
C. There is a $90$% chance that the sample mean is contained in this interval.
D. $90$% of the $40$ sample values will be within this interval.
You need to look very carefully at the exact wording in your text where confidence intervals are described.
If yours is a traditional frequentist text, then 'A' is the only "correct" answer. A Bayesian text would say 'C' is correct, but such a text would probably use the terminology 'probability interval' rather than 'confidence interval'.
You can probably find an example in your text where 'D' is obviously false. Answer 'B' is just silly; for example, if this is a confidence interval for a normal mean $\mu,$ then there are infinitely many 'population' values, and I'm not sure what 90% of infinity means.
Questions like this are intended to make you read explanations and definitions of your textbook very carefully. Because we do not have your textbook at hand, we can't do that for you. To do well in your course, you should understand exactly what 'rules' your text is playing by.