Which of the following is a TRUE statement about crossing over? A) Crossing over occurs in both mitosis and meiosis I.

B) Crossing over occurs during prophase I of meiosis; because of crossing over, genetic variation in the resulting gametes is increased.

C) Crossing over occurs in telophase II of meiosis; it decreases the genetic variability in the gametes produced.

D) Crossing over decreases genetic variation.