Two planes are perpendicular to one another. One of them contains vectors A and B, and the other contains vectors C and D. Which of the following relationships holds true?

A) A ⋅ C + B ⋅ D = 0
B) A ⋅ D - B ⋅ C = 0
C) A ⋅ B + C ⋅ D = 0
D) A ⋅ D + B ⋅ C = 0