Females Heterozygous for the Recessive Second Chromosome Mutations Px, Sp

Multiple Choice

Females heterozygous for the recessive second chromosome mutations px, sp, and cn are mated to a male homozygous for all three mutations.The offspring are as follows:
\begin{array}{|l|r|}\hline p x  s p  c n & 1461 \\\hline p x  s p  c n^{+} & 3497 \\\hline p x  s p{+ c n} & 1\\\hline p x  s p^{+}  c n+ & 11 \\\hline p x^{+}  s p  c n & 9 \\\hline p x^{+}  s p  c n+ & 0 \\\hline p x^{+}  s p+ c n & 3483 \\\hline p x^{+}  s p+ c n+ & 1539 \\\hline & 10,000 \\\hline\end{array}
-Which of the following linkage maps correctly shows the order and distance between the px, sp, and cn genes?

A) sp--0.21 m.u.--px--30.01 m.u.--cn
B) sp--30.01 m.u.--px--0.21 m.u.--cn
C) sp--0.2 m.u.--px--30 m.u.--cn
D) px--0.2 m.u.--sp--30.2 m.u.--cn
E) px--30.2 m.u.--sp--0.2 m.u.--cn