**Core Concept**
Crude birth rate (CBR) is a measure of the number of live births per 1,000 people in a population per year. It is an important demographic indicator used to assess the fertility rate and reproductive health of a population.

**Why the Correct Answer is Right**
The crude birth rate is influenced by factors such as fertility rates, mortality rates, and population age structure. In areas with higher CBRs, there may be lower socioeconomic status, limited access to family planning resources, and higher fertility rates among young women. The national level of CBR is often influenced by urbanization, education, and access to healthcare.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because urban areas often have lower CBRs due to increased access to education, family planning resources, and healthcare.
**Option B:** Incorrect because areas with high mortality rates, such as those with limited access to healthcare, may have lower CBRs due to high infant and maternal mortality rates.
**Option C:** Incorrect because areas with high mortality rates, such as those with limited access to healthcare, may have lower CBRs due to high infant and maternal mortality rates.

**Clinical Pearl / High-Yield Fact**
It's essential to note that CBR is a crude measure and does not account for variations in population age structure, which can affect the accuracy of the measurement.

**Correct Answer:** C.