A forced-choice design is often used to compare the attractiveness of pheromones to insects. A Y-tube is used. The pheromone is place on one branch; the control on the second branch; and the insect on the third branch. The insect then chooses one of the two branches. Suppose that28 of 70 insects choose the pheromone branch. The 95% plus-four confidence interval for the proportion of the population that prefers the pheromone branch is:

(0.525, 0.285)

(0.28, 0.70)

(0.285, 0.515)

(2.8, 7.7)