Database: student_club
Question: For all the club members from "Business" major, how many of them wear medium size t-shirt?
SQL: SELECT COUNT(T1.member_id) FROM member AS T1 INNER JOIN major AS T2 ON T1.link_to_major = T2.major_id WHERE T2.major_name = 'Business' AND T1.t_shirt_size = 'Medium'