Mycoplasmas are not sensitive to

Options

A. Penicillin
B. Streptomycin
C. Erythromycin
D. Neomycin.

Answer

### Step-by-Step Solution

1. **Understanding Mycoplasmas**: Mycoplasmas are a unique group of bacteria that lack a cell wall. They are the smallest living cells known and are known for their ability to survive without many of the structures found in typical bacteria.

2. **Sensitivity to Antibiotics**: One of the key characteristics of Mycoplasmas is their insensitivity to certain antibiotics, particularly those that target cell wall synthesis. Common antibiotics like penicillin and cephalosporins are ineffective against Mycoplasmas because these antibiotics work by inhibiting the formation of the bacterial cell wall, which Mycoplasmas do not possess.

3. **Conclusion**: Therefore, the correct answer to the question "Mycoplasmas are not sensitive to" is antibiotics that target cell wall synthesis, such as penicillin.