If n is a positive integer and n^2 is divisible by 18, then what is the largest positive integer that must divide n? Select
A) 3 B) 4 C) 6 D) 8 E) 9
18 =   2 * 3= 
<gadget id="calculator">  2 * 3</gadget>
<output>6</output>
6   The answer is 6.
<result>C</result>
If n is a positive integer and n^2 is divisible by 18, then what is the largest positive integer that must divide n?