this is a tough question in biology, could someone please help me.?

Question

The following data illustrates the relative locations of 4 genes on a chromosome:
Genes: A & D Frequency of Crossover: 5%
Genes: B & C Frequency of Crossover: 15%
Genes: A & C Frequency of Crossover: 30%
Genes: A & B Frequency of Crossover: 45%
Genes: B & D Frequency of Crossover: 50%

Which of the following represents the relative positions of these 4 genes on the chromosome?

A. BACD

B. ADCB

C. BCAD

D. CBAD

E. DCAB

Answer 1

Here's the logic. Use a piece of paper to follow along.
1. B and D are farthest apart. 50%
2. A is very near D, 5%, and A is pretty far from B, 45%. In fact 5 + 45 = 50, so put A between the first two genes and really close to D. So now you have B ...........................................A..D.
3. C is closer to B, 15%, than C is to A, 30%. And 15+30=45, so put C between B and A. Now you have B..........C..........................A....D.
4. Answer must be letter C: BCAD.