Explanation

p^3 = cos^2(theta)/sin(theta) and q^3 = sin^2(theta)/cos(theta), so (q/p)^3 = tan^3(theta) and tan(theta) = q/p. Hence option (B). Since both sides are real, taking cube roots of (q/p)^3 = tan^3(theta) gives q/p = tan(theta) directly.