Which condition indicates fluid retention in the abdomen?

Ascites is the correct choice because it specifically refers to the accumulation of fluid in the abdominal cavity. This condition often arises due to various underlying health issues, such as liver disease, heart failure, or certain cancers. The presence of excess fluid can lead to abdominal swelling and discomfort, and it can also affect the function of other organs within the abdomen.

In contrast, pneumonia involves inflammation of the lungs, which does not relate to abdominal fluid retention. Hemorrhage indicates bleeding, which could lead to fluid loss rather than retention. Dehydration is a state where the body loses more fluids than it takes in, resulting in reduced fluid levels, not an accumulation. Understanding these differences clarifies why ascites is the condition associated specifically with fluid retention in the abdomen.