In drosophila the two mutations stubble bristlessb and curle

In drosophila the two mutations stubble bristles(sb) and curled wing(cu) are linked on chromosome III. sb is a dominant gene and cu is recessive. If a female of the genotype

sb cu

+ +

is to be mate to detect recombination among her offspring what male genotype would you choose ?

how do I solve this kind of problem?

Solution

I found some mistake in question, plz do verify the question and let me know.

It might be sb and cu is recessive.