## Core Concept
Cross-resistance refers to the phenomenon where resistance to one drug confers resistance to another drug, often used to describe situations in antimicrobial therapy, particularly with antibiotics and antiretroviral drugs. This can occur through various mechanisms such as similar mechanisms of action, similar molecular targets, or shared resistance genes.

## Why the Correct Answer is Right
One-way resistance implies that resistance to drug A does not confer resistance to drug B, but resistance to drug B confers resistance to drug A. This type of resistance pattern can be observed in certain antibiotic classes. For instance, in the context of antiretroviral therapy for HIV, resistance to one class of drugs (e.g., nucleoside reverse transcriptase inhibitors) may not confer cross-resistance to another class (e.g., non-nucleoside reverse transcriptase inhibitors), but resistance to the latter can make the virus more resistant to certain drugs within the former class due to the distinct but overlapping resistance profiles.

## Why Each Wrong Option is Incorrect
- **Option A:** Without specific details on the drugs or classes in option A, it's difficult to assess directly, but generally, if a specific example is not illustrating a one-way resistance pattern accurately, it would be incorrect.
- **Option B:** Similarly, option B would be incorrect if it does not accurately depict a scenario of one-way resistance.
- **Option D:** Option D would be incorrect if it suggests a scenario that does not align with one-way cross-resistance.

## Clinical Pearl / High-Yield Fact
A key point to remember is that understanding cross-resistance patterns is crucial in the management of infections, particularly in the treatment of HIV and tuberculosis, where drug resistance is a significant concern. Clinicians must consider these patterns when selecting antimicrobial therapies to avoid inadvertently selecting for resistant strains.

## Correct Answer: C.