A cross among wild-type fruitfly Drosophila melanogaster [normal bristles and grey body (s+s, e+ e)] with a mutant fly [short bristles and ebony body (ss ee)] produces following progeny:
a) Normal bristles with grey body - 537 flies
b) Short bristles with ebony body - 542 flies
c) Normal bristles with ebony body - 76 flies
d) Short bristles with grey body - 75 flies
The map distance among 's' and 'e' genes will be: