Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-

Given : Sample size :
, which is a large sample , so we apply z-test .
Sample mean : 
Standard deviation : 
Significance level : 
Critical value : 
Now, a confidence interval at the 95% level of confidence will be :-

Correct answer is D).
A) and C) are polynomials, so x∈R, in B) we have √x, and in this case x ≥ 0.
Coercivity is the method a magnet loses its power