Consider the Pathway for the Synthesis of the Amino Acid

Multiple Choice

Consider the pathway for the synthesis of the amino acid arginine in Neurospora: $\begin{array}{c}\text { ornithine } \stackrel{\text { ARG-E }}{\rightarrow} \text { citrulline } \stackrel{\text { ARG-F }}{\rightarrow} \text { argininosuccinate } \stackrel{\text { ARG-H }}{\rightarrow} \text { arginine }\end{array}$
Mutant strains of Neurospora are grown in minimal media supplements as follows.Each mutant strain carries only a single mutation.Growth is shown by (+) ,no growth is shown by (o) . $\begin{array}{cccccc}&&&\text { Supplements }\\\text { mutant } & \text { nothing } & \text { ornithine } & \text { citrulline }&\text { arginino- } & \text { arginine } \\\text { strain } & &&&{\text { succinate }} \\\mathrm{a} & 0 & 0 & 0 & + & + \\\mathrm{b} & 0 & 0 & + & + & + \\\mathrm{c} & 0 & 0 & 0 & 0 & +\end{array}$
Indicate the correct pairing: mutant strain defective gene.

A) strain a ARG-F
B) strain a ARG-H
C) strain b ARG-F
D) strain c ARG-E
E) strain c ARG-F