From 5 positive numbers and 7 negative numbers, how many groups of 4 numbers, yielding a positive product, can be formed?  Choose the correct choice from the following:
A) 720 B) 625 C) 250 D) 960 E) 355
The number of ways to choose 4 positive numbers is 5C4 = 5.   The number of ways to choose 4 negative numbers is 7C4 = 35.   The number of ways to choose 2 positive and 2 negative is 5C2*7C2 = 10*21= 
<gadget id="calculator">10*21</gadget>
<output>210</output>
210.   The total number of groups is 5+35+210= 
<gadget id="calculator">5+35+210</gadget>
<output>250</output>
250.   The answer is 250.
<result>C</result>
From 5 positive numbers and 7 negative numbers, how many groups of 4 numbers, yielding a positive product, can be formed?