Standard error of the difference between the proportions of two variable can be computed by

A. $${\text{SE}}\left( {{p_1} - {p_2}} \right) = \sqrt {pq\left( {\frac{1}{{{n_1}}} + \frac{1}{{{n_2}}}} \right)} $$

B. $${\text{SE}} = p - 1\sqrt {\frac{{npq}}{{100}}} $$

C. $${\text{SE}} = \sqrt {\frac{p}{2} + \frac{q}{2}} $$

D. $${\text{SE}} = \sqrt {\frac{{npq}}{2}} $$

Answer: Option A