Answer:
The bacteria ate all of the available food.
Step-by-step explanation:
(B) is the most reasonable answer. At the start, it mentions that it's at the preferred temperature for the bacteria which rules out (C). It mentioned that the bacteria was growing which rules out (D) for saying it couldn't grow at all and I don't think (A) makes much sense. For even more backup for (B), it mentioned that the food was limited.