The Following Non-Complementing E A)14,9,10,21
B)9,10,14,21
C)10,9,14,21
D)21,14,9,10
E)10,21,14,9

Multiple Choice

The following non-complementing E.coli mutants were tested for growth on four known precursors of thymine,compounds A-D.The data provided in the table to reveal a simple linear biosynthetic pathway of the four precursors and the end product,thymine.In what order do the enzymes appear in this pathway (designate by their mutant number) ? $$\begin{array} { | l | l | l | l | l | l | } \hline \text { Mutant } & \text { A } & \text { B } & \text { C } & \text { D } & \text { Thymine } \\\hline 9 & + & - & + & - & + \\\hline 10 & - & - & + & - & + \\\hline 14 & + & + & + & - & + \\\hline 21 & - & - & - & - & + \\\hline\end{array}$$

A) 14,9,10,21
B) 9,10,14,21
C) 10,9,14,21
D) 21,14,9,10
E) 10,21,14,9