**Core Concept**
Plasmodium falciparum is a species of malaria-causing parasite that invades red blood cells (RBCs) and can lead to various hematological abnormalities. The peripheral blood smear (PBS) is a diagnostic tool used to identify these changes.

**Why the Correct Answer is Right**
In P. falciparum infection, the parasite invades RBCs and causes them to become larger and more irregular in shape. The parasite also consumes a significant amount of the RBC's hemoglobin, leading to a decrease in the RBC's hemoglobin content. This can result in a condition known as anisocytosis, where the size and shape of RBCs vary significantly. Additionally, the parasite can cause the RBCs to become fragmented, leading to schistocytes. Furthermore, P. falciparum infection can also lead to the presence of ring forms, trophozoites, and gametocytes in the peripheral blood smear.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because P. falciparum infection can indeed cause anisocytosis, which is characterized by variation in the size and shape of RBCs.
**Option B:** This option is incorrect because P. falciparum infection can also lead to the presence of schistocytes, which are fragmented RBCs.
**Option C:** This option is incorrect because P. falciparum infection can indeed cause the presence of ring forms, trophozoites, and gametocytes in the peripheral blood smear.

**Clinical Pearl / High-Yield Fact**
It's essential to note that P. falciparum infection can lead to severe complications, including cerebral malaria, if left untreated. Therefore, early diagnosis and treatment are crucial.

**Correct Answer: D.**