Final answer:
MIC is the lowest antibacterial drug concentration that inhibits visible bacterial growth, while MBC is the concentration that kills ≥99.9% of the bacteria. The correct answer to the student's question is D) Minimum Inhibitory Concentration, Minimum Bactericidal Concentration.
Step-by-step explanation:
The difference between minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) is fundamental in determining the effectiveness of antimicrobial drugs against bacterial infections. MIC is defined as the lowest concentration of an antibacterial drug that inhibits visible growth of a bacterial strain without necessarily killing the bacteria, often observed as a lack of turbidity (cloudiness) in broth during a dilution test. On the other hand, MBC refers to the lowest concentration of an antibacterial drug that kills ≥99.9% of the starting inoculum of bacteria. To determine the MBC, samples from the dilution test that show no visible growth (indicating MIC) are further cultured on agar plates without the antibiotic to observe the killing effect.