**Core Concept**
The World Health Organization (WHO) declared the outbreak of COVID-19 as a Public Health Emergency of International Concern (PHEIC) and later as a global pandemic, indicating a widespread and severe spread of the disease across international borders. This declaration triggers a coordinated international response to control the spread of the disease.

**Why the Correct Answer is Right**
The WHO declared COVID-19 as a global pandemic on March 11, 2020, citing the rapid spread of the disease and the increasing number of cases reported globally. This decision was based on the rapid increase in cases and hospitalizations, as well as the significant impact on global health systems. The declaration aimed to mobilize international cooperation and resources to combat the pandemic.

**Why Each Wrong Option is Incorrect**
**Option A:** This is not correct as the WHO declared COVID-19 as a Public Health Emergency of International Concern (PHEIC) on January 30, 2020, but not as a global pandemic.
**Option B:** This is not correct as the WHO declared COVID-19 as a global pandemic on March 11, 2020, not on any other date in March.
**Option C:** This is not correct as the WHO declared COVID-19 as a global pandemic on March 11, 2020, not on any other date in April.

**Clinical Pearl / High-Yield Fact**
The WHO's declaration of a global pandemic triggers a coordinated international response, including sharing of data, research, and resources to combat the disease.

**Correct Answer:** C. March 11, 2020