In a class of 100 students, every student has passed in one or more of the three subjects, i.e. History, Economics and English. Among all the students, 24 students have passed in English only, 14 students have passed in History only, 11 students have passed in both English and Economics only, and 12 students have passed in both English and History only. A total of 50 students have passed in History. If only 5 students have passed in all three subjects, then how many students have passed in Economics only?

Students have passed in English only = 24
Students have passed in History only = 14
Students have passed in both English and Economics only = 11
Students have passed in both English and History only = 12
Students have passed in History = 50
Students have passed in all three subjects = 5
Students have passed in Economics only = 100 - students have passed in History - students have passed in English only - students have passed in both English and Economics only = 100 -50 - 24 - 11 = 15
$$\therefore$$ The correct answer is option A.