**Core Concept**
Benign tertian malaria is a type of malaria caused by Plasmodium vivax. It is characterized by a 48-hour periodicity and typically affects the liver and red blood cells. The treatment of choice aims to eliminate the parasites from the bloodstream and prevent relapse from the liver stage.

**Why the Correct Answer is Right**
The treatment of choice for benign tertian malaria is chloroquine, which is effective against the erythrocytic stage of P. vivax. Chloroquine acts by inhibiting the parasite's heme detoxification pathway, leading to the accumulation of toxic heme and ultimately, parasite death. Additionally, primaquine is often used in combination with chloroquine to eliminate the liver stage (hypnozoites) of P. vivax, preventing relapse.

**Why Each Wrong Option is Incorrect**
* **Option A:** Quinine is an alternative treatment for malaria, but it is not the first-line treatment for benign tertian malaria caused by P. vivax.
* **Option B:** Artemisinin-based combination therapies (ACTs) are effective against P. falciparum, but they are not the preferred treatment for P. vivax.
* **Option D:** Doxycycline is an antibiotic that can be used as a prophylactic agent for malaria, but it is not the treatment of choice for benign tertian malaria.

**Clinical Pearl / High-Yield Fact**
It is essential to note that primaquine should be used with caution in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, as it can cause hemolysis.

**Correct Answer: C. Chloroquine**