If angle A and angle B are complementary angles, which of the following is true?

Complimentary angles ADD to 90 degrees.

     then   A+B=90      so   B= 90-A

    SO the FIRST choice is obviously true!   (and the last choice is NOT true (except at 45 degrees))

The second and third are basically the same statement.  (they are both true)   

   Draw a right triangle    one angle is 90 degrees   the other angles total 90 degrees (A and B)

     Now look at this diagram:    For any right triangle you can draw (which means A and B add to 90 degrees)     You can see that for compimentary angles  cos A = Sin B