In a group of 68 students, each student is registered for at least one of three classes – History, Math and English. Twenty-five students are registered for History, twenty-two students are registered for Math, and thirty-five students are registered for English. If only three students are registered for all three classes, how many students are registered for exactly two classes?	Choose the correct choice from the following choices.
A) 13 B) 10 C) 9 D) 8 E) 7
A U B U C = A + B + C - AB-BC-AC + ABC   68 = 25 + 22+ 35 -AB-BC-AC +3 =&gt; AB+BC+AC = 17   Exactly Two classes = AB+BC+AC - 3ABC = 17 -3*3= 
<gadget id="calculator">17 -3*3</gadget>
<output>8</output>
8   Hence 8
<result>D</result>
In a group of 68 students, each student is registered for at least one of three classes – History, Math and English. Twenty-five students are registered for History, twenty-two students are registered for Math, and thirty-five students are registered for English. If only three students are registered for all three classes, how many students are registered for exactly two classes?