**Core Concept**
The management of hospital waste is a critical aspect of infection control and public health. Hospital waste is categorized into different types, including infectious waste, non-infectious waste, and recyclable waste. Understanding the proportion of infectious waste is essential for implementing effective waste disposal strategies and minimizing the risk of disease transmission.

**Why the Correct Answer is Right**
Infectious waste in hospitals includes items contaminated with blood, bodily fluids, or other potentially infectious materials. According to the World Health Organization (WHO) guidelines, infectious waste accounts for approximately 1.5% of total hospital waste. This percentage may vary depending on the hospital's size, patient population, and infection control practices. However, 1.5% is a commonly cited estimate in the literature. The correct answer reflects the relatively small proportion of infectious waste compared to other types of hospital waste.

**Why Each Wrong Option is Incorrect**
**Option B:** 4.5% is an overestimation of the actual proportion of infectious waste. This percentage is not supported by any credible sources and may lead to unnecessary concerns about waste management.
**Option C:** 25% is a gross overestimation and is not based on any scientific evidence. Such a high percentage would have significant implications for waste disposal and infection control practices.
**Option D:** 12% is also an overestimation and is not consistent with the available literature on hospital waste management.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the proportion of infectious waste can vary depending on the hospital's patient population and infection control practices. For example, hospitals with a high number of surgical procedures or patients with infectious diseases may have a higher proportion of infectious waste.

**Correct Answer:**
✓ Correct Answer: A. 1.50%