Consider the following data derived from a test cross of a female fruit fly that was heterozygous for the recessive, autosomal loci scarlet eyes (st), shaven bristles (sv), and ebony body (e):

Phenotype #observed phenotype #observed
+ st sv 227 + + + 17
e st sv 15 e + sv 232
e + + 245 + + sv 13
e st + 13 + st + 238

(a) Use this data to determine whether zero, two, or three of these genes are linked. Diagram the correct genotype of the heterozygous female parent. Indicate linkage (coupling or repulsion of alleles).
(b) Determine the map distance between all linked genes.