Correct Answer:
B. ناتجربه کار
The phrase "طفل مکتب" (Tifl-e-Maktab) literally means 'school child' or 'student'. Idiomatically, it refers to someone who is new, naive, or ناتجربه کار (inexperienced) in a particular field or situation. It implies a lack of practical knowledge or expertise, similar to a beginner.