If x and y are positive integers, and x^3*y^4 = 27783, which of the following is the value of xy?	Choose the correct choice:
A) 6
B) 10
C) 14
D) 15
E) 21
27783 = 3*9261 = 3^2*3087 = 3^3*1029 = 3^4*343 = 3^4*7^3   xy = 3*7= 
<gadget id="calculator">3*7</gadget>
<output>21</output>
21   The answer is 21.
<result>E</result>
If x and y are positive integers, and x^3*y^4 = 27783, which of the following is the value of xy?