Evaluation of the performance of large language models in responding to medical questions related to multiple sclerosis: A case study of large language models including ChatGPT, Gemini, Grok and Copilot - Meisam Dastani; Mohammad Shayan Sajjadi; Bassem Yamout; Melika Arab Bafrani; Amirreza Nasirzadeh (PLoS ONE, 2026)