The third proportional to 1 and 2 is?  Choose the correct choice from the following
A) 2
B) 1
C) 4
D) 8
E) 7
(2*2)/1= 
<gadget id="calculator">(2*2)/1</gadget>
<output>4</output>
4   Answer: 4
<result>C</result>
The third proportional to 1 and 2 is?