Question 1131776
The point estimate is the best guess and that is 1038/2640 or 0.393
the half-interval is z(0.95), for two sided confidence interval, * sqrt (p*(1-p)/n); the sqrt term is the standard error of the mean.
=1.645*sqrt(0.393*0.607/2640)
=0.0156


The CI is the point estimate+/- z*SE or 0.393+/-0.0156
(0.3774, 0.4086) 

This means that one is 90% confident that the true value, unknown and unknowable is in this interval.  That is C.  
A is not true because the population proportion either does or doesn't fall in the interval, it isn't moving around.
B is not usually true ever except in small populations.
D refers to doing many sample proportions, and 90% of them will contain the population parameter.  We don't know which 90 those are, however.