To determine the correct life cycle of Plasmodium, we need to analyze the options provided and compare them with the known life cycle of the Plasmodium parasite, which causes malaria. The life cycle involves both human and mosquito hosts and includes several stages.
### Step-by-Step Solution:
1. **Understanding the Life Cycle**:
- The life cycle of Plasmodium begins when a female Anopheles mosquito bites an infected human and injects sporozoites from its salivary glands into the human bloodstream.
2. **Initial Infection**:
- The sporozoites travel to the liver cells (hepatocytes) where they undergo asexual reproduction (schizogony). This stage is crucial as it allows the parasite to multiply.
3. **Release into Bloodstream**:
- After a period of development in the liver, the liver cells burst, releasing merozoites into the bloodstream, which then invade red blood cells (RBCs).
4. **Asexual Reproduction in RBCs**:
- Inside the RBCs, the merozoites continue to multiply asexually. This stage leads to the destruction of RBCs and the release of more merozoites, which can infect additional RBCs.
5. **Formation of Gametocytes**:
- Some of the merozoites develop into gametocytes within the RBCs. These gametocytes are crucial for the next stage of the life cycle.
6. **Transmission to Mosquito**:
- When a mosquito bites an infected human, it ingests the gametocytes along with the blood meal. Inside the mosquito, the gametocytes undergo sexual reproduction, forming zygotes that develop into sporozoites.
7. **Sporozoite Development**:
- The sporozoites migrate to the salivary glands of the mosquito, ready to be transmitted to another human host during the next bite.
8. **Cycle Repeats**:
- This cycle continues as the mosquito bites another human, starting the process over again.
### Conclusion:
Based on the above understanding, we can analyze the options:
- **Option A**: Incorrect, as it states sporozoites go to RBCs before the liver.
- **Option B**: Correct, as it follows the proper sequence of sporozoites being injected by a mosquito, going to the liver, then to RBCs, and finally forming gametocytes.
- **Option C**: Incorrect, as it incorrectly states that sporozoites go to humans directly.
- **Option D**: Incorrect, as it suggests a sequence that does not align with the life cycle.
Thus, the correct answer is **Option B**.
