Based on your description, though I cannot see the graph, the answer can be inferred depending on the typical interpretation of growth curves and pH levels.
If Bacteria A shows maximum growth at around pH 7, then the correct answer would be:
a. Bacteria A grows best in a medium that is neutral.
If the graph indicates that Bacteria A shows peak growth in the slightly basic range (above pH 7 but not reaching high levels), then the correct conclusion would shift to:
b. Bacteria A grows best in a medium that is slightly basic.
However, if Bacteria A thrives in lower pH levels (between 0-6), then:
c. Bacteria A grows best in a medium that is slightly acidic.
Finally, if the growth looks optimal at a high pH (above 10), the conclusion would be:
d. Bacteria A grows best in a medium that is very basic.
To accurately answer the question, one would need to observe the specific data points on the graph regarding Bacteria A's growth in relation to the pH levels.