The correct answer is option The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
In case, two genes are present in very close proximity to one another, they would represent the phenomenon of linkage. Due to the the presence of the linkage between the two closely related genes, the crossing over between them would not occur. As the distance between the two genes is decreased, the linkage becomes more strong and reduced the chances of the crossing over. Hence, it can be said that the chance of the crossing over between two genes varies according to the distance between them.
