Each of the 48 members in a high school class is required to sign up for a minimum of one and a maximum of three academic clubs. The three clubs to choose from are the poetry club, the history club, and the writing club. A total of 15 students sign up for the poetry club, 23 students for the history club, and 21 students for the writing club. If 3 students sign up for exactly two clubs, how many students sign up for all three clubs? Choose the correct choice from the following answers.
A) 3	B) 4	C) 5	D) 6	E) 7
The total number in the three clubs is 15+23+21= 
<gadget id="calculator">15+23+21</gadget>
<output>59</output>
59.   All 48 students signed up for at least one club.   3 of those students signed up for exactly one more club.   59 - 51= 
<gadget id="calculator">59 - 51</gadget>
<output>8</output>
8 so 4 students must have signed up for exactly three clubs.   The answer is 4.
<result>B</result>
Each of the 48 members in a high school class is required to sign up for a minimum of one and a maximum of three academic clubs. The three clubs to choose from are the poetry club, the history club, and the writing club. A total of 15 students sign up for the poetry club, 23 students for the history club, and 21 students for the writing club. If 3 students sign up for exactly two clubs, how many students sign up for all three clubs?