How many odd factors does 520 have? Select the correct option.
A) 3  B) 4  C) 5  D) 6  E) 8
Start with the prime factorization: 520 = 2*5*13   For odd factors, we put aside the factor of two, and look at the other prime factors.   set of exponents = {1, 1}   plus 1 to each = {2, 2}   product = 2*2= 
<gadget id="calculator">2*2</gadget>
<output>4</output>
4   Therefore, there are 4 odd factors of 520.   Answer: 4.
<result>B</result>
How many odd factors does 520 have?