A Plantlike Organism on the Planet Pandora Can Have Three

Multiple Choice

A plantlike organism on the planet Pandora can have three recessive genetic traits: bluish leaves,due to an allele (a) of gene A;a feathered stem,due to an allele (b) of gene B;and hollow roots,due to an allele (c) of gene C.The three genes are linked and recombine.
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and was able to identify progeny of the phenotypic distribution (+ = wild type) shown in the figure below.
The greatest distance among the three genes is between a and c.What does this mean?

A) Gene c is between a and b.
B) Genes are in the order: a-b-c.
C) Gene a is not recombining with c.
D) Gene a is between b and c.