**Core Concept**
Antibiotic sensitivity testing is a crucial procedure in microbiology that determines the effectiveness of various antibiotics against specific bacterial isolates. This process is essential for guiding clinicians in selecting the most appropriate antibiotic for treating infections. The **Kirby-Bauer disc diffusion method** is a commonly used technique for this purpose.

**Why the Correct Answer is Right**
The correct answer is related to the method used for antibiotic sensitivity testing. The **Kirby-Bauer disc diffusion method** involves placing antibiotic-impregnated discs on agar plates inoculated with the bacterial isolate. The zone of inhibition around each disc indicates the susceptibility of the bacteria to the respective antibiotic.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not directly related to the standard methods used for antibiotic sensitivity testing.
**Option B:** This option is also incorrect as it does not represent a commonly used technique for antibiotic sensitivity testing.
**Option C:** This option is incorrect because, although it might be related to microbiological testing, it is not specifically used for antibiotic sensitivity testing.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that antibiotic sensitivity testing is vital for preventing the misuse of antibiotics and for combating antibiotic resistance. Clinicians should always consider the results of these tests when prescribing antibiotics.

**Correct Answer:** D. Kirby-Bauer disc diffusion method.