<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 21-year-old woman is diagnosed with a rare subtype of anti-NMDA encephalitis. During the diagnostic workup, she was found to have an ovarian teratoma. Her physician is curious about the association between anti-NMDA encephalitis and ovarian teratomas. A causal relationship between this subtype of anti-NMDA encephalitis and ovarian teratomas is suspected. The physician aims to identify patients with anti-NMDA encephalitis and subsequently evaluate them for the presence of ovarian teratomas. Which type of study design would be the most appropriate?? A: Cross-sectional study, B: Case series, C: Case-control study, D: Randomized controlled trial, E: Retrospective cohort study,  <response>: This is a question asking about the appropriate study design to evaluate a suspected causal relationship between anti-NMDA encephalitis and ovarian teratomas. The key points are:- Rare subtype of anti-NMDA encephalitis is suspected to be causally related to ovarian teratomas- The aim is to identify patients with anti-NMDA encephalitis and evaluate them for teratomas- Evaluating a suspected causal relationship between a diseasecondition and a risk factorGiven this, the most appropriate study design would be a prospective cohort study. This allows identifying patients with the disease anti-NMDA encephalitis and following them forward in time to evaluate for the outcomerisk factor presence of ovarian teratomas. This establishes the temporal relationship needed to evaluate causation.Cross-sectional and case studies do not evaluate temporal relationships. Case-control is retrospective. Randomized trials are not feasible or ethical here.C: Case-control study 