A random sample of 240 adults over the age of 40 found that 144 would use an online dating service. Another random sample of 234 adults age 40 and under showed that 131 would use an online dating service. Assuming all conditions are met, which of the following is the standard error for a 90 percent confidence interval to estimate the difference between the population proportions of adults within each age group who would use an online dating service?

(the big one without a number outside the radical)
The sampling distribution of the difference in sample proportions is approximately normal.
The normality of the sampling distribution of the difference in sample proportions cannot be established