Table 203 the Following Data Were Obtained from a Broth Dilution

Table 20.3 The following data were obtained from a broth dilution test:
$$\begin{array}{|l|}\begin{array} { c | c } \hline \text { Concentration of Antibiotic }\\ \text { X } & \text { Growth } \\\hline 2.0 \mu \mathrm { g } / \mathrm { ml } & - \\\hline 1.0 \mu \mathrm { m } / \mathrm { ml } & - \\\hline 0.5 \mu \mathrm { g } / \mathrm { ml } & - \\\hline 0.25 \mu \mathrm { gl } / \mathrm { ml } & + \\\hline 0.125 \mu \mathrm { g } / \mathrm { ml } & + \\\hline 0 & + \\\hline\end{array}\end{array}$$
Bacteria from the 0.25 μg/ml tube were transferred to new growth media
Containing antibiotic X with the following results:
$$\begin{array}{|l|}\begin{array} { c | c } \hline \text { Concentration of Antibiotic }\\ \text { X } & \text { Growth } \\\hline 2.0 \mu \mathrm { g } / \mathrm { ml } & - \\\hline 1.0 \mu \mathrm { m } / \mathrm { ml } & + \\\hline 0.5 \mu \mathrm { g } / \mathrm { ml } & + \\\hline 0.25 \mu \mathrm { gl } / \mathrm { ml } & + \\\hline\end{array}\end{array}$$
The data in Table 20.3 show that these bacteria

A) are pathogenic.
B) developed resistance to antibiotics.
C) were killed by 0.125 μg/ml of antibiotic X.
D) were killed by 0.5 μg/ml of antibiotic X.
E) were resistant to 1.0 μg/ml at the start of the experiment.