Suppose that a survey was taken of 50 people and each person was asked if they approved or disapproved of the president's actions during the government shutdown. Thirty people said that they approved. Which of the following statements correctly describes how the confidence interval for the population proportion of people that approved the President's actions during the government shutdown?

A. There are not 15 observed successes and 15 observed failures. A confidence interval can be computed by adding 2 successes and 2 failures.

B. There are at least 15 observed successes and 15 observed failures. A large sample confidence interval for the population proportion can be computed (phat +/- z * sqrt(p*(1-p)/n) with no additional values added.

C. There are not 15 observed successes and 15 observed failures. A confidence interval can not be done.

D. There are not 15 observed successes and 15 observed failures. A confidence interval can be computed by adding 4 successes and 5 failures.