What is the sum of the different positive prime factors of 720?  Select the correct option.
A) 5  B) 10  C) 15  D) 17  E) 21
Prime factorization of 720   =72 * 10   =6*12 * 10   =2*3 * 2*6 * 2*5   =2*3 * 2 * 2*3 * 2*5   =2^4 * 3^2 * 5   Sum of the different positive prime factors of 720 = 2+3+5= 
<gadget id="calculator">2+3+5</gadget>
<output>10</output>
10   Answer 10
<result>B</result>
What is the sum of the different positive prime factors of 720?