Interference occurs when: A.)two genes are assorting independently. B.)two genes are far apart on a genetic map. C.)one crossover inhibits another. D.)the number recombinant progeny classes in the testcross of a heterozygote exceeds the number of parental progeny. Solution Answer : The correct answer is C (one crossover inhibits another.). The tendency of one crossover to interfere with the other cross over is called interference.