This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
A client is recently diagnosed with HIV and a highly antiretroviral therapy is started. After the first week of therapy, the patient complains of headache, dizziness, and nightmares. Which one of the following anti-retroviral drugs is most likely associated with these symptoms? 
Select and explain. 
A. Lamivudine., B. Efavirenz., C. Tenofovir., D. Saquinavir.
B: Efavirenz.
Answer: B: Efavirenz. 
Explanation: Efavirenz is a non-nucleoside reverse transcriptase inhibitor. Side effects include rash, dizziness, confusion, headache, and nightmares.

Options A and C: Lamivudine and Tenofovir side effects includes headache, dizziness, nausea, diarrhea, or trouble sleeping.
Option D: Saquinavir can cause headache, nausea, diarrhea, and photosensitivity.