**Core Concept**
The disposal of used medical waste, including urine bags, is governed by guidelines to prevent infection and maintain a safe environment. The use of color-coded bags is a standardized system to categorize different types of medical waste.

**Why the Correct Answer is Right**
The correct answer is based on the color-coded system used for medical waste disposal. Used urine bags are considered infectious waste and require proper disposal to prevent the spread of pathogens. The yellow bag is used for infectious waste, which includes items contaminated with bodily fluids, such as urine, feces, and blood.

**Why Each Wrong Option is Incorrect**
**Option A:** The red bag is used for anatomical waste, which includes human tissues and organs.
**Option B:** The white bag is used for non-infectious waste, which includes items like disposable gloves, syringes, and medical supplies that have not come into contact with bodily fluids.
**Option C:** The blue bag is used for sharps waste, which includes items like syringes, needles, and scalpels that have been used for medical procedures.

**Clinical Pearl / High-Yield Fact**
Remember the color-coded system for medical waste disposal: red for anatomical waste, yellow for infectious waste, blue for sharps waste, and white for non-infectious waste.

**Correct Answer:** B. Yellow bag.