Double crossovers can involve two, three or four strands at a

Double crossovers can involve two, three or four strands at a time. What will be the resultant percentage of recombined genes to normal genes in between which recombination occurred, taking all three types in consideration?

A. 0%

B. 50%

C. 70%

D. 90%

I got this question at a job interview.

I need to ask this question from Linkage and Crossing Over topic in portion Genetic Recombination of Cytogenetics

Right choice is B. 50%

Explanation: Taking all types of a double cross over in consideration only 50% of the resultant will show recombination between the genes which are located on two sides of these recombination events.