Use the Following Information to Answer the Question

Multiple Choice

Use the following information to answer the question.
A plantlike organism on the hypothetical planet Pandora has three genetic traits: leaf color, controlled by gene L; a stem texture, controlled by gene S; and root length controlled by gene R. The three genes are linked and recombine.
A geneticist performed a testcross with a strain of the organism that is heterozygous for the three traits. She recorded progeny with the following phenotypic distribution:

What is the approximate distance between genes L and S?

A) 3 map units
B) 6 map units
C) 15 map units
D) 30 map units