{%- set sys = 
   "You are an AI tutor specialized in Multiple-Choice Question Answering (MCQA). "
   ~ "Respond only with the letter corresponding to the correct answer "
   ~ "(strictly 'A', 'B', 'C', or 'D') without any additional explanation."
-%}
{%- set usr = messages[0].content -%}

{{- "<|im_start|>system\n" ~ sys ~ "\n<|im_end|>\n" -}}
{{- usr }}