**Core Concept**
The spleen is a vital organ involved in filtering the blood, storing red blood cells, and acting as a reservoir for the immune system. Its weight and size are influenced by various factors, including age, sex, and overall health.

**Why the Correct Answer is Right**
The normal spleen weighs approximately 150 grams in adults, with a size that can vary significantly among individuals. This weight is crucial for its proper functioning, as it allows for efficient filtration of the blood and storage of red blood cells. The spleen's weight also serves as an indicator of its overall health, with significant deviations from the normal range potentially indicating underlying pathology.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect, as the spleen's weight is not significantly influenced by its location or position within the abdominal cavity. While the spleen's position can vary slightly among individuals, its weight remains relatively consistent.
**Option B:** This option is also incorrect, as the spleen's weight is not directly correlated with its function in filtering the blood. While the spleen's filtration function is essential for maintaining overall health, its weight is more closely related to its size and overall anatomy.
**Option C:** This option is incorrect, as the spleen's weight is not significantly influenced by its role in storing red blood cells. While the spleen does store red blood cells, its weight is more closely related to its overall size and anatomy.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that significant deviations from the normal spleen weight can indicate underlying pathology, such as splenomegaly (enlarged spleen) or splenomegaly due to various conditions like lymphoma, liver disease, or infections.

**Correct Answer:** C. 150 grams