If [math]A[/math] and [math]B[/math] are independent, which of the following is always true?

• [math]A[/math] and [math]B^c[/math] are also independent
• [math]A^c[/math] and [math]B^c[/math] are not independent.
• [math]A^c[/math] and [math]B[/math] are not independent.
• [math]A\cap B[/math] is independent of [math]A[/math].
• [math]P(A\cup B) = P(A) + P(B)[/math].