**Core Concept**
The measles vaccine is a live, attenuated vaccine produced through the cultivation of the measles virus in a specific cell culture. The strain used for vaccine production must demonstrate a balance between immunogenicity, safety, and consistency.

**Why the Correct Answer is Right**
The Edmonston-Zagreb strain of the measles virus is used for the production of the measles vaccine. This strain was developed from the Edmonston strain by further attenuation and is known for its high immunogenicity and low virulence. The Edmonston-Zagreb strain is cultivated in chick embryo cell cultures, which provides a suitable environment for the virus to replicate and produce the vaccine antigen.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because the Schwarz strain is used for the production of the mumps vaccine, not the measles vaccine.
* **Option B:** Incorrect because the Moraten strain is used for the production of the yellow fever vaccine, not the measles vaccine.
* **Option C:** Incorrect because the Rubeola strain is an older strain of the measles virus, but it is not the specific strain used for modern measles vaccine production.

**Clinical Pearl / High-Yield Fact**
The measles vaccine is a critical component of routine childhood vaccination schedules and is highly effective in preventing measles infection and its complications, including measles pneumonia and encephalitis.

**Correct Answer:** C. Edmonston-Zagreb strain.